"RTN" is an acronym that stands for "Return to Normal," which means going back to a previously established state or routine. Synonyms for this phrase include "revert," "go back," "return," "resurrect," "revive," "restore," and "reinstate." These words all convey the idea of going back to a previous condition or situation. Other synonyms for "RTN" could include "recuperate," "recover," "refresh," "renew," "regenerate," and "reset." Overall, using synonyms can be a great way to add variety to your language and clarify your meaning, especially when it comes to concepts like "returning to normal".