To be clear: rests are only filling out the measure to have the correct number of beats. If you don't plan to add more notes in the measure, then having the rests there saved you the trouble of entering them yourself. if you do plan to add more notes, just do it - the rests will simply be overwritten.
Comments
You don't. Why would you want to? MuseScore just tries to ensure that every measure is complete
To be clear: rests are only filling out the measure to have the correct number of beats. If you don't plan to add more notes in the measure, then having the rests there saved you the trouble of entering them yourself. if you do plan to add more notes, just do it - the rests will simply be overwritten.