hi
When a credit memo is applied to a sales invoice, it creates a link between the two documents, and this link can prevent the reversal of the sales invoice. In this case, you will need to first remove the credit memo application from the sales invoice, and then reverse the sales invoice.
To remove the credit memo application from the sales invoice, follow these steps:
Open the sales invoice that has the credit memo applied.
Click on the "Credit Memo" tab, and select the applied credit memo.
Click on the "Delete Application" action in the ribbon.
Once you have removed the credit memo application, you should be able to reverse the sales invoice by clicking on the "Reverse" action in the ribbon.
Keep in mind that reversing a sales invoice will create a new document, which will have a negative value and will be posted to the same accounts as the original invoice, reversing the impact of the original transaction.
DAniele