If one said sim shalom in the maariv shmoneh esrei instead of shalom rav what should he do?
What happens in the reverse case if one said shalom rav at shaachris, does he fulfill his shmoneh esrei?
Shulchan Aruch 127:2
The Rema says that we say Sim Shalom any time we have a tefilah that is fitting for the blessing of the Kohanim to be included.
This is based on the end of the discussion of the Shemoneh Esrey in Talmud Megillah 18. The Amidah should end with a longer and more specific blessing of Shalom to end the tefilah.
Mishnah Berurah to 127:2 (13) with The Biur Halachah says:
The Ari-zal's custom (hence, the custom of Chassidim) is to say Sim Shalom all the time.
If someone said Sim Shalom instead of Shalom Rav, then that is OK.
If someone said Shalom Rav instead of Sim Shalom (even by Shachris), then that is OK too.
Although one should say the right passage for their nussach, we do not repeat the Amidah or that paragraph for such a mistake. (Except that the Biur Halachah is unsure whether to restart the paragraph in the morning, if he notices his error before saying the closing blessing.)