HARMONY will do that quite easily.

One away is to use Create a new tune
You tell it the time signature, key and number of bars you want.

It will create a score and fill each bar with rests. You then just drag and drop the notes onto the rests (replacing them).

Alternatively, paste the new notes after each bar line and then delete all the rests.

You can then play the tune - it will add chords and an accompaniment as well, if you like. Or you can drag and drop the chord names of your choice onto notes, and generate the accompaniment from that.

It does run under XP.