ADD / REMOVE PARTY MEMBER STORED IN VARIABLE

Hello,

I'm trying to set something up so that if you press shift button, the order of the party changes. There's three party members, and pressing shift changes the order.

Example:

Burns > Albert > Zack (initial order)
(Shift is pressed)
Zack > Burns > Albert
(Shift is pressed)
Albert > Zack > Burns
(Back to initial order when shift is pressed)

Now this wouldn't be much of a problem if these were the only party members, but I'm trying to make this dynamic so it works for any party. Basically when you press shift, the guy in the front goes to the back and the other two move up a notch.

I thought the event command "Add / Remove Party Member Stored in Variable" might be useful in this process, but I've never used it and I wonder how it works. How do you "store" the ID of a character in a variable?

Some elaboration would be nice.