I had to do that a few weeks ago. We were traveling with a young woman who has many, many food allergies. I had asked her to make me a list of what she would like to have in the room (stayed at OKW in a studio). She never responded. So, I made my own order, and got the slight discount for ordering early. Well, the week before we left, she emailed me, apologizing profusely, and asked if she could have some things ordered. I was able to just add those things to my existing order....no early order discount at that time though!! Worked out quite well...even if she only ate 1/3 of the stuff I ordered and paid for!!