smooth over
US /smuːð ˈoʊvər/
UK /smuːð ˈoʊvər/

1.
calmer, minimiser, aplanir
to make a problem or difficulty seem less serious or important than it really is
:
•
He tried to smooth over the argument between his friends.
Il a essayé de calmer la dispute entre ses amis.
•
The manager tried to smooth over the customer's complaints with a discount.
Le gérant a essayé de minimiser les plaintes du client avec une réduction.