
Mark Returns Authorisations as Locked to prevent any further changes from being made to the Invoice.
From Orders List View select and display Returns Authorisations only

You can make a selection of Return's Authorisations and use the Bulk Action to mark them as Locked at once
Please see Manual on Bulk Actions
..or you can mark an individual Return's Authorisations as Locked
Click on the RA number to access the Return's Authorisations.
