Remining balance on billing - to voucher

Hello,

Do you mean that the guest has paid more than the booking value, and instead of refunding the excess amount, you would like to keep it to be used toward the next stay?

Yes, we are trying to sort out our ledgers and allocate this remaining balance to a voucher.

Okay, in that case, I would create a product called “Voucher” and add it to the open bill to balance it.
I would then create an external payment mapped to the same account as the product and post a payment for the same value on a new open bill.

Alternatively, you can wait to post the external payment until the guest stays with you again and brings the voucher with them (if a physical voucher was issued).

This article explains the process outlined above by ​@Robin Gustavsson if it helps: How to manage gift vouchers?

Set up an external payment type, post a negative payment equaling the “refund” to the bill, and a positive payment amount to a new bill, invoice (close) the first bill, move payment from the open bill to the bill for the new stay? If no stay is immediately booked, just let it lie there since bills are under guest profiles anyways.

Will this not see the revenue as entered twice, which would incur income tax on both amounts?

How would we track the issued vouchers, if they are not created as, far as I can see, they would only be corporate vouchers, which can be created, and this would be more of a discount code?   

I would handle it more like a gift card, if that makes sense. I’m not fully sure what you mean by a voucher.
We only use vouchers in Mews as keys to unlock different rate plans.