calm down
US /kɑːm daʊn/
UK /kɑːm daʊn/

1.
to become quiet and relaxed after being angry, excited, or upset, or to make someone do this
:
•
Please, just calm down and tell me what happened.
•
She took a deep breath to calm down.
to become quiet and relaxed after being angry, excited, or upset, or to make someone do this