The phrase "go off well" refers to something that was successful and without any issues. There are plenty of synonyms that one could use to describe this type of success. For instance, the use of phrases like "went smoothly," "happened without a hitch," "went off without a hitch," "went without a problem," or "went according to plan" would all be effective ways to describe a successful event. Other similar phrases that could be used include "went off without a hitch," "went as planned," "successful execution," or "flawless outcome." By using such synonyms, one can enhance the description of a positive event and highlight its success.