I sent a letter and SAE with US stamp on to the Stage Manager on: 29th April 2014, and on Monday I recieved this signed programme back from the stage manager signed by the cast, plus he sent a note back, saying its been signed by the writer and director too.
address I used was:
Stage Manager of ' The International',
The Cell,
338. W 23rd St,
New York
NY 10011
USA
Did you literally write "Stage Manager of The International" on your envelope, or did you use the real name of this person?
(That's a genuine question. I have no idea how to find out the name of the stage manager of any play.)