Requesting for extension of ceremony schedule

Hi,

Would it be possible to request for an extension, even just a few days, from the Home Office regarding the citizenship ceremony?

The situation is my partner received the Home Office invitation letter dated 30 Jan but accdg to our local register, the deadline is before 28 April. I thought we were able to book the ceremony within 90 days / 3 mos? So we thought could book it until at least 30 April.

Unfortunately, we already booked travel plan just before those dates and the earliest availability would be on April 29 (just a day after the deadline). The register advised us that we can request for an extension to the HO. Anyone care to share their experience with this? Or if this is even possible?

Thanks again!