Convert from/to compound meter
As far as I know currently there is no any way to convert score from/to compound meter (with saving measures). For example, convert from 4/4 with triplets to 12/8. Essentially compound time is a way to simplify notation, like elimitating triplets from 4/4.
Unfortunately, I found no way to make this conversion automatically. The only solution is manually rewriting whole score! Even copy-paste doesn't work.
It's not a such big deal to make the conversion automatically because in fact this is just multiplying every note's duration by a constant. E.g. to conversion 4/4 -> 12/8 is multiplying each note to 3/2.