Double the time value of every note in a score.

I have a score, uploaded here, that is played rather slowly. In fact, too slowly.
So I'd like to double the time value of every note and rest in the score, i.e., every quarter note becomes a half note, every eighth note becomes a quarter note. Same for rests. A quarter rest becomes a half rest, an eighth rest becomes a quarter rest, etc.
Obviously, the score would now contain twice as many measures, but I could now use a decent tempo and counting for the musicians would be easier.
I could, of course, re-enter the entire score, but is there a quicker way to do this ??
Thank you.