What spell can i use to clam someone down?

I'm sure someone somewhere out there would be willing to suggest a spell to calm someone down, but in truth, it is not likely to work.

Magic is not a snap your fingers, wave a wand and make the world a perfect place kind of thing.

Most of the ethical practitioners of my acquaintance will tell you that magic is for things that need magic. Mundane things usually have a mundane solution.

Calming someone down is a mundane need. Try talking to this person in a reasonable manner, perhaps an apology might help, or more likely, just plain old communication will help the situation.