The phrase "be in concurrence" refers to the agreement or consensus between two or more parties regarding a particular matter. There are several synonyms that can be used to express the same meaning, such as "be in agreement," "be of the same mind," "be on the same page," "be in harmony," "be in sync," "be unanimous," and "be in accord." All of these terms highlight the idea of mutual understanding, cooperation, and compatibility. Using such synonyms properly can make your writing more effective by enhancing clarity and precision, while avoiding repetition and redundancy, ultimately making your message more impactful.