Hi @Nutth0,
I specifically have a 'dummy listing' or 'ghost listing' for situations like these. I keep this ghost listing inactive at all times until I have a special situation like this come up. The ghost listing should also always have instant book turned off(ALWAYS).
For this situations specifically:
1. While it's 'Unlisted' match the price on each day on the ghost listing to the same daily price of the different rooms it's accounting for. Make sure your cleaning fee is correct.
2. Block the days that will be booked on the calendar for the normal listings and make sure those dates are available on the ghost listing.
3. Activate the ghost listing and send the offer to your guest with notes about which days and times room switch will happen. Make sure there are notes in the actual listing description as well stating this is a room combination.
4. Once reservation is booked, you can immediately unlist the ghost listing again, the reservation will stay booked.
Cheers.