Hi, I have a master dataset (a) which contains recently merged variables from another dataset (b). I was sent another dataset (c) which has some variables that I want to merge into my master dataset (a). When I tried using the merge command (See below), I received an error message saying "variable _merge already defined". I read somewhere that it's possible to do it on older versions of STATA but is it possible on STATA 16.1? Thank you.

Code:
 merge 1:1 METAKEY using cascades_merge_ART