[broker] an agreement

to help negotiate and facilitate a deal or compromise between parties with differing interests or positions

The skilled mediator helped broker an agreement between the warring factions.
The union representative played a key role in brokering an agreement with the company.
Diplomats from different countries are working together to broker an agreement on trade tariffs.
The real estate agent successfully brokered an agreement between the buyer and seller.
He is known for his ability to broker agreements in challenging political situations.