Persistent Spell: Patron's Assuagement

By channeling the mind of your patron while you cast a warlock spell that requires concentration, you can give burden of that concentration to your patron. Doing so allows you to maintain concentration on a separate spell yourself. When you are forced to make a concentration check, roll separately for each spell. Your patron can only be used to concentrate on a spell if you expend a spell slot to cast it.

Keeping the mind of your patron channeled is taxing. While your patron is concentrating on a spell for you, you cannot use your action to attack. Though you can still activate the effects a spell that you or your patron is concentrating on.