no not really ,unless its hot glued and you can use heat .If its joined with epoxy glue it is a very fine window to soften the glue and not "stuff" the shaft or blade ($$$), I suggest a splitter (called sleeve in OZ) or a new shaft (and remove the old one mechanically) what brand paddle is it and how much do want to shorten it by ? Lats
I do this very often By The Way.