idk i got so used to the old actress that seeing someone new makes it feel fake. i think if the old actress didn't wanna continue they should shoot one scene with her bag leaving or if she really couldn't or didn't want to they could put text or something. anyway i think changing the actress instead of gettng rid of the character is bad decision. but im not a director nor writer so don't trust my opinion
p.s no hate towards ji woo (the new actress) at all