Pidyon HaBen on the wrong day

Hi,

There is a debate as to whether Pidyon HaBen may be done after the baby's 30th day ends at nightfall, or whether it must wait until the baby has lived an entire lunar cycle, which is a little more than 29.5 days. Thus a baby born just before nightfall on July 1 will be eligible for Pidyon HaBen after nightfall on July 30 according to the first view, but the second view will still require more time. We follow the second view.

If a family mistakenly invited guests for a Pidyon HaBen on the night after the baby's 30th day, and there would be great shame in informing the guests of the error and re-scheduling the Pidyon HaBen, then they may proceed with the Pidyon HaBen at the advertised time, to avoid embarrassment.

(Rav Moshe Feinstein, Igrot Moshe Yoreh Deah 1:196)

Have a great day,
Mordechai