Most of the fields are greyed out on a paid bill or part paid bill, the only way to edit these details is to remove the payment(s) and return the bill to the unpaid tab.
There are two ways to remove a payment, you can de-allocate it and re-allocate after you have made changes, or you can delete the payment and re-create it in future.
If the bill has been included in a submitted VAT return you will be unable to delete the bill so will need to reverse it instead.
Navigate to Purchases > Bills > All.
Click on the bill number that you would like to edit.
The payments allocated to the bill will appear in the Payment history table at the bottom.
At this stage, you can either choose to delete or de-allocate the payment.
Deleting the payment will mean you will need to re-create the payment again it at a later date.
De-allocating the payment will allow you to remove the payment from the bill and re-allocate it again in future.
You will need to repeat this process for all payments if there are more than one.
Please note: If you are on a cash accounting VAT scheme and the payments have been included on a submitted VAT return, you will be unable to delete or de-allocate. If you have made a mistake or duplicated, you can reverse the paid bill using the guide below:
Once the bill has been corrected, you can re-create a payment and allocate to the bill or you can re-allocate the payment you deallocated in Step 3 by clicking on the Allocate button when viewing the bill.