An invitation to dine in someone's home, whether offered in person or in writing, usually requires a prompt response. The host needs to know how many people to expect at the gathering.

• If you see "R.S.V.P." (a French acronym meaning "please respond") on an invitation, you must respond whether or not you plan to attend. If a telephone number is included, call the host promptly with your response. If a return card is offered, return it by the date requested.
• When no R.S.V.P. is present, you need not respond; however, it is OK to do so, and chances are your host will appreciate it. If the invitation says "regrets only," you should only contact the host if you do not plan to attend.
• If you cannot accept the invitation, or want to keep the evening open, decline politely. Once you have accepted an invitation, you are obliged to attend unless a crisis arises.