Can I cash in points and use a buy one get one free MyVegas reward?

I purchased a buy one get one free dinner voucher for MGM. Can I use my M Life points to 'buy' the one dinner and the other will be free with the voucher?

Doubtful, but you can charge the "bought" one to your room, use the points at check-out to pay for it.

Normally you can't use an offer with any other offer. Not sure is the answer - give it a try at the cashier and see what they do is probably the best way to find out. Or charge the dinner to your room as 02bn suggests. You should definitely get the reduced M Life member dinner price if nothing else, I expect.