Answer:
   
   The following are some of the changes made by Conservative Judaism in
   regular prayers:
     * Birkhot HaShakhar - Morning Blessings
       Three of the early morning berakhot were modified to praise God
       for having created each individual in God's image, a free person
       and a Jew, rather than the conventional version which express
       gratitude for not having been created a woman, a slave or a
       non-Jew. Details on this modification can be found in "Siddur Sim
       Shalom - A Halakhic Analysis", Conservative Judaism, Vol.41(1),
       Fall 1988.
       Conventionally Birkhot HaShakhar contains a number of passages
       describing sacrifices and offerings in ancient times which can
       only be recalled, not carried out. Most of these passages are
       deleted from the Silverman Siddur, and even more from Siddur Sim
       Shalom. The sacrificial ritual in ancient times was construed as
       means by which a Jew gained atonement for sin. After the
       destruction of the Temple and the consequential end of sacrifices
       there, the Jewish people were deprived of this means. To replace
       the readings on sacrifices, modern Conservative prayerbooks cite
       the talmudic teaching that deeds of loving-kindness now atone for
       sin; they draw upon rabbinic tradition to emphasize teachings
       about atonement and necessary behavior.
       Texts that have been added to this part of the service include
       Leviticus 19:2, 14-18, Avot de Rabbi Nathan, 11a and Tractate
       Sukkah 49b.
     * Al HaNissim and the State of Israel
       An innovation in Conservative prayer books is a liturgical
       response to the creation of the modern State of Israel. It was
       felt that this should be made in a manner that is integral to the
       fabric of the service; Such a liturgical model already existed: Al
       HaNissim, which is added to the service on Purim on Chanukah. Thus
       a new, third Al HaNissim was composed, adapting the language and
       style of the standard Hebrew text to produce a text that is used
       on Yom Ha'Atzmaut, Israel's Independence Day. A Torah and Haftarah
       reading for this day is also indicated. In the Al Hanissim
       prayers, Siddur Sim Shalom follows the text of Rav Amram Gaon,
       emending the text which expressed gratitude for miracles "in other
       times, at this season" to now read "in other times, and in our
       day". This adds a basic theological dimension that miracles are
       not confined to a remote and unavailable past.
     * Sacrifices in the Amidah
       "Siddur Sim Shalom" presents multiple alternatives for the Shabbat
       Musaf, but the Orthodox version that explicitly prays for the
       resumption of animal sacrifice in a rebuilt Temple is not one of
       them. Instead, Siddur Sim Shalom adopts an innovation from "The
       Shabbat and Festival Prayerbook" in the Musaf Amidah; it changes
       the phrase na'ase ve'nakriv (we will present and sacrifice) to asu
       ve'hikrivu (they presented and sacrificed). The petition to accept
       the "fire offerings of Israel" is removed from the Amidah.
       There are similar modifications in the Rosh Hodesh Amidah. "Siddur
       Sim Shalom for Shabbat and Festivals" does not present multiple
       services; it presents one musaf for Shabbat, for festivals, and
       for Rosh Hodesh. Within each service, the reader is offered a
       traditional text, as well as an alternative text which eliminates
       mention of sacrifices. The traditional Y'hi Ratzon meditation
       ("May it be your will, Adonai our God, and God of our Ancestors,
       that the Temple be restored in our day...") following the Musaf
       Amidah is restored. This is also restored in Va'Ani Tefilati.
     * Other changes in Musaf
       Following a modification found in the siddur of Rav Saadiah Gaon,
       the Hebrew word ba-olam (in the world) is added to the daily
       prayer for peace at the end of the Amidah, making explicit the
       traditional Jewish concern for universal peace. A prayer for the
       welfare of the community, recited following the Torah service on
       Shabbat, was modified to include a phrase commending those who are
       devoted to helping rebuild the Land of Israel.
     * Tahanun - supplications following the weekday morning Amidah
       The earliest sources about saying Tahanun is from the Tosefta in
       Berakhot; The Geonim viewed this section as optional, the contents
       were flexible as well. In his Siddur Maimonides also makes it
       clear that there are various customs and he is merely citing his
       own custom. Originally this point in the service was considered
       appropriate for the personal supplications of each individual, and
       it still is. Over the years, however, certain stylized passages
       were printed as the fixed text; these contain references to the
       physical desolation of Jerusalem and statements of extreme
       self-abasement. To reflect present reality, such statements have
       been deleted, other passages have adapted or abridged, and brief
       portions of supplications by Rav Amram and Rav Saadiah Gaon have
       been added. These are closer to us in spirit than many passages of
       later origin which were canonized by the printing press. One's own
       prayers are appropriate, and traditional.
     * Egalitarian Hebrew formulations
       The language of liturgical formulas in Siddur Sim Shalom reflects
       the reality that in many congregations both men and women
       participate in the service. Some prayers include references to
       both the patriarchs and the matriarchs. Passages designed for use
       on Simchat Torah include texts appropriate for formally
       designating women as well as men as honorees on that occasion. The
       prayer on behalf of the congregation (recited after the Torah
       reading on Shabbat) has been emended to reflect the fact that
       women as well as men are members of the congregation. The Mi
       Sheberakh prayers contain forms for both male and female readers.
       The meditations prior to putting on the tallit and tefillin
       provide masculine and feminine forms.
     * Nahum, on Tisha B'Av
       Tisha B'Av commemorates the days on which both the First and
       Second Temples were destroyed. The conventional text (Nahum)
       speaks of Jerusalem as "a desolate and vacant city", laid waste
       and deserted. These lines no longer bear any relation to reality.
       As such the new text recalls the tragedy of ancient times, over
       which we mourn, and recalls the desolation of Jerusalem in the
       past. It also speaks of a "Jerusalem rebuilt from destruction and
       restored from desolation". It asks that all who mourn Jerusalem of
       old rejoice with her now, and it prays for the peace of that city.
     * Shoah (Holocaust) Remembrance
       "Siddur Sim Shalom" (original version) adds many passages for Yom
       HaShoah that can be added to any weekday service, as well as a
       formal reading. Several pages of readings are included in the
       supplementary section for addition to any of the services held on
       that day, and are followed by a formal reading arranged for
       responsive use. The section concludes with a Mourner's Kaddish
       similar in structure to the one on Yom Kipur.
     * Mysticism and Hasidism
       A surprising mystical and Hasidic influence appears in Siddur Sim
       Shalom, as is illustrated by the numerous additions to the prayer
       book which originated in these movements. The blessing for the new
       moon (kiddush levanah) appears at the end of the Sabbath liturgy.
       Another mystical element is the Raza DeShabbat, the "Vision of
       Shabbat", which precedes the Sabbath evening service. Taken from
       the Zohar, this passage depicts the enthronement of the Shekhinah.
       Several of the alternative meditations which follow the amidot
       stress joy, and request freedom from atzvit (sorrow) in classic
       Hasidic fashion. In fact, a number of these passages are based on
       the teachings of Rabbi Nachman of Bratslav. Some benedictions for
       mitzvot are preceded by kavanot (meditations) which were
       introduced into the liturgy by the Kabbalists.
     * Adding Matriarchs to the Amidah
       Two positions have been accepted by the Conservative movement on
       this issue. One position states that, for a variety of reasons, it
       is wrong to add the names of the Matriarchs to the Amidah. A
       second position advances a halakhic argument that shows that such
       changes are permissible. In all cases where the law committee has
       validated more than one possible position, a congregation must
       follow the ruling of its rabbi, who as mara d'atra [local halakhic
       authority] has the sole responsibility and authority in making
       such a p'sak [decision].
       Note: When presenting the Matriarchs in the opening passage of the
       Amidah, Conservative/Masorti siddurim do not add the word
       "Imoteynu" (our Matriarchs), as the word "Avoteynu" is held to be
       correctly understood as "our Ancestors", and not as "our
       Patriarchs".
       
   To better understand Conservative teshuvot and siddurim one should be
   familiar with the findings of modern liturgical scholarship; this has
   demonstrated not only the flexible nature of the liturgy in general,
   including the Amidah. Suggested references:
     * "Liturgy" entry in the "Encyclopaedia Judaica" Ismar Elbogen and
       Raymond P. Scheindlin.
     * "Jewish Liturgy: A Comprehensive History", JPS, 1993.
     * Louis Finklestein's article on the Amidah in the "Jewish Quarterly
       Review" (new series) volume 16, (1925-1926), p.1-43
     * Joseph Heinemann "'Iyyunei Tefilla" Magnes, Jerusalem, 1981
     * Seth Kadish "Kavvana: Directing the Heart in Jewish Prayer" Jason
       Aronson Inc., 1997
     * Jakob J. Petuchowski "Contributions to the Scientific Study of
       Jewish Liturgy" Ktav, NY, 1970
     * "Who knows four? The Imahot in Rabbinic Judaism" Alvin Kaunfer.
       Judaism Vol 44. Winter 1995, p. 94-103