I had the problem with an actor (male lead) changing a line in the show because he thought it sounded better or was was funny or somesuch ( it was long ago when i was a young stage manager and I forget exactly why). It was an exit line for the scene and of course his version was terrible; more to the point, it wasnt as written. It was a new work, so there had been lots of rewriting and i expect all the cast felt a bit of text ownership, but we did have a playwright! The actor and I had gotten on well until now.
The first time I gave him a line note. He explained he'd done it on purpose. I said, please dont. he did it again. I told him not to in small words. he did it again. I wrote in the show report " Mr X changed exit line Sc X, has been asked not to do this' No one from management commented or got back to me. I am getting all worked up and actor and I are annoying each other a lot! I write it in the show report again. Finally the Director calls ( from 2500kms away) and I ask him if its Ok with him. He says no way, tell Mr X to stop. I relay the message. Actor stops. we continue to be polite but not superfriendly with one another.
A few weeks later we tour the show to Sydney, Mr Xs hometown. all the other cast are from Perth, where we rehearsed and opened the show. Between seasons we have a week off, Mr X at home in Sydney.
On day one of the Sydney season, Mr X comes to me and, out of the blue, apologises for his behaviour in Perth regarding the line. I suddenly realise he had been feeling hugely stressed without the director still there to support him, and without his usual networks . he was quite young ( so was I I guess!).
I was glad then that I had always stayed professional, and even though i had taken his refusal to deliver the line as written as a personal affront I hadn't behaved like it was personal.
Of course now I think about this incident and laugh. I was a baby stage manager. now i doubt the actor would have defied me, and if he had i would have done exactly as i did but the situation wouldnt have got to me. I would have left it on the show report and gone home and forgotten about it.