Bentching

If one forgets Ya’aleh Veyavo but remembers before saying Hashem’s name at the end of Bonei Yerushalayim, he goes back. If one remembered after that, but before beginning the next Brocho, he recites the extra Brocho printed in the Bentcher. If one already began even the first word of the next Brocho, one must begin bentching again at night, but not during the daytime.

Both the Horachamon of Yom Tov and Rosh Hashana are recited, in that order.

One does not add a Hey when saying Oiseh Sholom in bentching.