change time signature and notes

I wrote a fanfare in Musescore, in 2/4 time, quarter-note =50. It was confusing for the band, so I directed it in 4/8 at 100. Very confusing. I want to rewrite it in 4/4 at 100, which means, changing all the quarter notes to half notes, all the sixteenths to eighths, etc. Is there a clever way to do this, so that I don't have to write the whole thing over again. (I know, I could just change the time signature to 4/8, but that would be confusing, too.)
thanks
TR