OK, briefly, the space my group rents is owned by the park district who receives the rent $ and the booking is managed by a restaurant upstairs. The room is also periodically rented out for weddings, reunions, etc. and the restaurant has exclusive catering rights to the room. Twice in a row now we have confirmed dates with the manager of this restaurant only to have her come back when it's too late for us to change anything and tell us the room is double booked and we have to let people wander around our set and props unsupervised. The first time there wasn't a timing conflict as they needed the room in the early afternoon and would be out by the time we needed to rehearse, however the restaurant did take our very heavy risers and shove them behind the stage and curtain and then failed to show up to move them back. This time they are telling us that there has been a wedding booked into the room for over a year and we won't be able to have a Sat. performance on opening weekend! Also we can't set up our risers until Sun. morning! We've received no offer of compensation for the time they are being doubly paid for, and the attitude from the rest. manager is unconcerned at best. If the wedding was booked a year ago, why did you confirm the dates with us?   And if you were a bride who had had a venue booked for over a year, wouldn't you be angry to show up and learn that only 2/3 of the room is available to you and you can't set up until the morning of the wedding? There's really nothing to be done because this is the ONLY viable venue in our area which makes the board timid about standing up and complaining, but I just had to vent about it, it's giving me heartburn.

I agree get them to sign off on all comfirmed dates. the when they pull this, pull out your signed contract. then it is there problem

We have the same problem - we do not own any performance space and we have to rent our venue.  The venue is a lovely, restored 1800 Opera House that seats 310. However, often something gets planned that we have to work around after we signed our contract for certain rehearsal dates. There is never a problem with actual show dates. I have learned to ask for simpler sets that can be removed easily.  No one like change, but it actually has been kind of nice. Our strikes are always fast - then on to the cast party - hoorah!

You don't say how much you are paying for this space but maybe if you got a written contract and then requested a refund for the times you had to share the space it would stop pretty quickly.  They shouldn't be collecting double rents for the same space.  Have you considered an outdoor production in the summer?  Lots of new problems but new challenges too.