Expand note durations to replace rests

When entering a melody, I often start with a series of rests or repeated notes, and then adjust the measure to yield a result comprising short-duration notes, eighths or sixteenths, separated by rests. This leaves room for inserting notes or adjusting rhythm. Then later I go through and expand the durations to replace the rests, by selecting each note preceding a rest and changing its duration, adding dots, etc.. (Think of starting with staccato and ending with legato.}

Is there any mechanism that would assist this process, I.e. a tool that expands all selected note durations to replace rests? I know it's an odd way to work but at times it's a faster process for me.