Changing the dimensions of Flash movie

Does anyone know how to change the dimensions of a flash movie (fla), I know to change it in the modify document, the problem is that I already have a complex movie, when i try to resize the document everything needs moved and is totally a real pain.

is there an easy way of doing this, sort of crop tool or resize document to the middle (cut the outsides off it) ?

any help greatly appreciated. :red: