My friend in grammar school had a Leap Day birthday and his parents' solution was that his birthday was celebrated "the day after February 28th".

I went to high school with twins born on the 29th. If I remember correct they celebrated on the 28th.

My aunt and an uncle (coincidentally, the same aunt's daughter's husband) are both born on Leap Day and they celebrate the 28th.

Although their shared party is on the 2nd this year since it's a Saturday.