I needed to add a couple to some of our dining reservations for our recent trip. Our initial reservations were for large groups, so instead of trying to increase our total reservation by 2, I just looked for a reservation for 2 at the same restaurant at the same (or close) time. I was able to get everything I needed before we left, and most restaurants were gracious about seating us together even though we had two separate reservations. I think checking in early helped with this, and I never expected them to seat us together, I just hoped they could.

The only problem is that you can't make a second reservation for the same meal online using your account. You can call the dining line and have them make a second one for you - which can result in missing out if someone else snatches up a time before you can get through to them - or you could have your friend make the additional reservation on their account (or you could log in as them and make the reservation on line).

Good luck!