Guests arriving in 3 weeks. Now want to change booking from 4 nights to 3

Guest booked our 4 BR place last March of 2025 for ski vacation later this month. He messaged me this morning that two of the couples that are coming have just informed him that they need to leave a day early. He now wants to change the booking so they all leave a day early.

>Is there any possibility this point of changing then rental to check out Sunday instead of Monday? Just seeing if its an option. Thanks!

He hasn't directly asked for money, but that would seem to where he's headed.

I have in the past decided to leave a hotel or STR early and done just that, left. He didn't say that he and his wife have to leave. I guessing she figures why stay if they're going to be alone.

I am under no obligation to refund as far as I know. Part of me is thinking they are trying, if possible, to get around my 4 night minimum for this time of the year (Park City, UT). I only rent out place from late December through early April. By booking this so early, he effectively took the day he now wants to give me back off the table for renters this season

What would you all do?