You’re supposed to return the engagement ring (now that’s hilarious!!!)
You have to send back all the gifts with a brief explanation why it was cancelled.
(So don’t use anything until you say, "I do".)
It’s written that if a gift is engraved or personalized, you don’t have to return
it.
Don’t speak poorly of your ex because somewhere down the line you might get back
together. (Darsi added this one all by herself.)
You should inform out-of-town guests first so that they can change or cancel their
travel and lodging arrangements.
If you’re postponing your wedding, of course every guest has to be contacted. Etiquette
pros say that you have to send another invitation with the new date.