Can I change the room rate on a historic reservation?

Once the overnight accommodation charge has been posted you cannot override the rate.

If the guest was charged too little you would then need to add a transaction charge for the outstanding balance by clicking "Add Transaction" select the transaction type as "Charge" add a description and select the article for your accommodation revenue".

If the guest was charged too much then you would need to add a discount transaction to clear the outstanding balance. 

To do this click "Add Transaction" and select the Transaction Type as "Discount" you have the option to add a discount value.

Or you can choose a percentage by ticking the "Apply a percentage discount".