To see or talk to someone at some later, unspecified time or date. Used especially when one is unable to converse at the current moment. I'd love to hear more about your trip, but I really have to go now—I'll catch you some other time, OK?
https://www.usingenglish.com/reference/idioms/some other time.html
synonyms for at that time. Compare Synonyms. again. formerly. later. next. suddenly. all at once. anon.
one at a time; one by one; personally; restrictedly; severally; singly; without help
Once upon a time. "Once upon a time" is a stock phrase that has been used in some form since at least 1380 in storytelling in the English language, and seems to have become a widely accepted convention for opening oral narratives by around 1600. These stories often then end with "and they all lived happily ever after," or, originally, "happily until their deaths."
https://www.definitions.net/definition/once upon a time
doc for "another word for another time".(Page 1 of about 18 results)