Finale 2007 question

I have written the song in 2/4 but now I want to change to 4/4 but I want to preserve all the note values which were written in 2/4.

I'm not quite sure what you mean by "note values" ; do you mean you want to switch to 4/4 time and keep all the note values the same proportionately? So you want, for example, 4 sixteenth notes and a quarter note to turn into 4 eighth notes and a half note?

If you just want to keep the note lengths the same and merely "redistribute them" to the 4/4, simply check "Rebar Music" in the Time Signature dialog box. (Unless your version of Finale somehow doesn't have this.)