Changing enharmonic spelling?

I just spent way too much time changing the enharmonic spelling in an orchestra-to-band transcription from sharps to flats for easier reading. I made the changes in the score, only to discover that they didn’t carry through to the parts. I can’t find any way around that, so I guess I’m going to have to go through the parts now and do it all over again.

Am I missing something?

Propagate Properties.

Changing enharmonics in the score normally does Propagate automatically - it’s the other way (parts to score) that doesn’t work.