Let's assume that you are going to be late for a meeting. I wonder when do you normally use each sentence below?
1) I’m sorry for keeping you / to keep you waiting.
- I would use this sentence both before seeing the person who is waiting me e.g. through a phone call while I'm in the taxi and called them and using this sentence as an apology.
2) I am sorry to have kept you waiting.
- I think it can be used only when you reach the person who you have kept him waiting on the meeting and you'e going to apologize him in this way.
I wonder what do you think?