How can I call the leader to remind the meeting?

Hello! XX, is it convenient to talk now?

You will have a meeting later to remind you that X is in XX meeting room. Just checked at the door, and all the other XX people have arrived! Can I help you prepare anything?

Remember, be sure to finish asking, otherwise the leader will not tell you if there are other rejections.

This is the end of the question. Anyway, the leader will reply! But the result may not matter!