Opening night changes are never a good thing but they are inevitable and can either be an opportunity for excellence or failure. And the only way to test and see which way it falls, is to try. I would like to advise that you avoid making changes as much as possible–they are, more often than not, pitfalls for both actors and crew.
These kind of changes are sometimes avoidable and other times unavoidable. For instance–substituting a shirt for another can seem harmless, even potentially a positive change as it can possibly provide an actor with an easier change between scenes. But it isn’t what you rehearsed with–you haven’t learned how the shirt sits and shifts on your body. You may not even know how to put it on (I’m talking about closures such as zippers and buttons–Velcro, even, can be difficult).
I think what’s most important, when a director or staff member decides to make changes, is to properly ensure the decision is made with reasonable and sound judgment. It’s also important to be cognizant of the type of person(s) to whom these changes impact–it might not be in their best interest to make last minute changes, it could throw off their performance groove and negatively impact the show. Let me just say, sometimes its better to live with a mistake you made in pre-production than make another during production.
‘Til next time.
Oh, and this post? It was written from many, many real life experiences I recently had from a production I am heavily involved in.