Past tense of RSVP [duplicate]

In formulating past tenses of unlikely words or acronyms, an apostrophe-d is always used to prevent confusion or mispronunciation. (Obviously this is non-issue in speech.) You could also use the auxiliary do if you want to avoid this construction. These two sentences are thus correct:

• Only one person RSVP'd to my event.
• Only one person did RSVP to my event.

Also, keep in mind that whenever acronyms are put in past tense using the apostrophe-d formulation, no account is taken of the full logical meaning of the acronym. Thus, you have examples like

• DIY'd (which means engaged in a DIY project or carried out DIY on, etc),
• BS'd,
• SWAK'd (sealed with a kiss),

and so forth.

RSVP (Répondez S'il Vous Plaît — reply if you please/please reply) is a special acronym because it functions as a verb. However, we have all found it convenient to take it away from its largely stiff, formal original context (e.g. RSVP: Mr. Jones) to more useful ones, such as:

• Don't forget to RSVP.
• I did not RSVP. Can I still come?
• Anyone planning to come should RSVP, so I know how many burgers to buy.
• Please RSVP ASAP! (never mind the repetition!)

The past tense is less common, but RSVP'd would be the correct way to write it down.