The antonyms for the phrase "act as broker" would be "dissolve," "disconnect," or "separate." These antonyms connote the opposite meaning of bringing parties together for a deal or agreement, instead implying a cessation of relations or the breaking apart of a partnership. Acting as a broker implies a level of trust and mediation between parties, whereas these antonyms indicate a lack of trust, cooperation, and collaboration. Inverting the meaning of the verb phrase illustrates the importance of communication, willingness to work together, and the mutual benefit that brokers can bring to those seeking successful transactions.