If you want to say, 'I have an appointment with~', it is easy to think of 'I have a promise with~' instead, because of the word 'promise.' However, it is an awkward expression. A promise is a statement which you make to a person in which you say that you will do something or give them something. For example, "If you make a promise, you should keep it." Therefore, it is more natural to say, "I'm meeting up with a friend today" or " I've got plans with family today" in this situation.

L.L.F reporter You-Jin Kim