I work ith music to video, I think a general start promt for characters and staging could help if we want to have the same charachters in different sceenes and situations, and then we could ask for these charachters in different surroundings.

Here it seemes you have to change it, then copy it, then delete it and paste it before you generate. Else you will risk loosing the changes you made and end up with no change at all.