The phrase "at an end" refers to the conclusion of an event or situation. There are several synonyms for this phrase, including "finished," "completed," "concluded," "terminated," "ended," "closed," "wrapped up," and "resolved." Each of these words implies the finality of the situation, with no further action required. Whether it be a project, a relationship, or a task, using one of these synonyms can add variety and depth to your language. It can also help you emphasize the importance of the finality of the situation, emphasizing that the event in question has truly come to an end.