It cannot be done directly. Only way I can see to do it would be to block on the new place's calendar and then adjust the original reservation on the other calendar to one night. But that also triggers things like releasing the deposit and review prompting... so you'll want to think about this. HA is not a reservation system like a hotel where you can just move people between locations, that's not their model.
I get this a lot and have mentioned it on the Community several times. I have 6 properties and guests often need to switch for financial reasons, mobility, date changes, group size and a whole host of other factors.
Airbnb offers a 'change reservation' feature which allows a host to change the dates, property, etc and send it to the guest for acceptance. In my view, this is a huge benefit to the guest experience as well as the host. It makes changes more seamless of hosts and guests, and ensures that reservations aren't changed without the consent of both host and guest.
Unfortunately. VRBO/HA doesn't offer this option. The best way I've found to handle it is to have the guest full-out cancel and then rebook them.
There are several risks with this, both for you and for VRBO/HA. The risk, of course, is that the traveler may end up booking something else all together once they are canceled with you. There's no way to be sure that they'll take your property or even book through VRBO/HA, other than have them make the new reservation before canceling the old. I had this happen once when the guest realized that the service fee was inexplicably higher on the new booking than on the old. I generally see it happen with guests who have become annoyed with VRBO/HA because of technical, payment or other issues. Guests seem to understand that we have no control over these issues, but it can cause you to loose a booking if they have no other way to book with you.
I have tried some of the 'work around' situations that were mentioned before by feibus. Just as he suggested this causes ridiculous headaches and confusion due to calendar inaccuracies. It is also very confusing to guests to have multiple reservations like that. I've been fortunate to never have a chargeback or had to withhold a security deposit but with this kind of work around I've always been concerned that in the case of a chargeback or need to hold the deposit the fuzzy calendar-keeping would be hard to explain.
Hope that helps.