Hi~Firstly,I want to congratulations on your new opening.
This is XXX, a Diamond Elite member of your hotel group. I reserved a King Guest Room for 1 night, from xx to xx.
This is my first stay in your hotel and it's also my wife's birthday.I'm planing to invite some local friends of my wife to celebrate together in our room.So could you please try to upgrate our room to a suite if the room is aviable.
Thank you very much and looking forward to your reply~