Convert time signatures

Hi,

Does anyone know a way to convert time signatures using Musescore? (or another tool would do)

I've been given some music that should clearly be written as quavers in 6/8 but it's written as tripleted crochets in 4/4. I tried a couple of programs to see if there was a way to convert but i can't see the option anywhere. Before i bore myself senseless going through 4 verses tweaking the notes I thought I'd ask if such a tool exists?
Thanks

Russell