Insert a beat in project?

You didn't say whether you wanted to add material in the extra beat or just lengthen on note in the measure. I'm assuming you want to add a rest.
I know there's a better way but this is what I did

Copy up the the measure in question and paste somewhere else... say track 50 or below your original.

Insert change you want in the measure you want in the original (changes it for entire project). Say from 4/4 to 5/4.
Insert the change back in the next measure (5/4 to 4/4)

Copy and paste the remaining stuff from the original (measure in question on) and paste where you want it after the first paste. Like one beat to the right or left or whatever.

If that works can delete all the original and there you are. Cut and paste what you made to track 1.

I ran into problems with tempo changes but not big deal for my piece.

John

Done it, thanks guys!:)

Haha, I followed your instructions. Though I didn't find a 'dialog' - so it changed the old signature.
The markers stayed where they were so they are now a beat before the bar..no worries! That was one of the things that made me think I'd messed up my project before. I did have to drag all the audio and MIDI over,too :)