Two of the Upper East Side’s biggest Jewish institutions, Park East Synagogue and Chabad-Lubavitch of the Upper East Side, are joining forces and starting Rosh Hashanah, it’s going to change what a night (or a Shabbat, or a Tuesday) out looks like uptown. Here’s the gist: Park East, the landmarked 1890 sanctuary on East 67th … Park East Synagogue and Chabad UES are merging programs starting this Rosh Hashanah