The phrase "has to oneself" can be replaced by several synonyms, depending on the context. For instance, "keeping to oneself" is often used to describe someone who prefers to be alone, or who does not share their thoughts or feelings with others. "Having privacy" or "being secluded" are also synonyms, referring to the need to have a space or time that is exclusively one's own. In some cases, "has to oneself" might indicate a requirement or obligation, such as "must handle alone," "needs to do individually," or "should bear responsibility." Regardless of the precise connotation, it is important to understand the context to find the best synonym.