Adding another mpc: switching between one and a live

I recently started working on a project with a guy who uses an mpc one- I use a live. I figured I could easily disconnect mine from controller mode and then connect his to post some of same samples on, etc.
His never entered controller mode, and I can’t remember exactly what I did when I originally connected mine? Is there something I’m forgetting? Shouldn’t I be able to alternate between the two?

Perhaps I'm thinking too easily, but couldn't you guys send eachother .xpj files?

Awesome, thanks- I didn’t even think about the project files.

No problem at all!