Guest adding a night to already paid booking

I'm wanting to offer my guests a discount for extending their stay, or coming in a day earlier, to help cover one night gaps in my calendar. How do I go about this exactly when they have already paid for their trip up front?

Thanks

Felicia 

Here are our general instructions for extending a stay:

https://www.ownerrez.com/support/articles/extending-a-stay

This process is very convoluted and appears to be far from "one size fits all".  Is it not possible to autogenerate a quote from your direct booking listing and auto-send that in a triggered message to provide the offer?  The only reason I can think of why one would care where the extension came from (i.e., from the originally booked platform or the direct-booking source) is that they would likely need to enter in their payment credentials on the new source (direct-booking) rather than it pulling automatically from the original source (such as Airbnb).

It would be simple enough to add in a better discount to extend through your direct-booking source, but still provide the option to extend via the original source.

Is this possible through OR, or through some third-party integration, or does this need to be a feature request?

Part of the issue here is the TOS'es of the various listing channels, that restrict or disallow extending bookings off-platform.  Since we have partnership agreements with the channels, we cannot intentionally design features to easily violate their policies, though there may be manual workarounds that we don't actively obstruct.