To change the Review Date when checking in a document, the document must first have been checked out with Review selected as the reason. If a document is checked out with the reasons Change or Formatting, when checking the document back in the Review Date is greyed out and not able to be changed.
The workaround for this is to check the document back in after filling in the mandatory fields and reason for change; Check the document out again and select Review as the reason, change the Review Date and check in.
NB. Prompt Admin - if checking out documents for review or updating, select Review as the checkout reason. Selecting the checkout reasons Change or Formatting should only be done for minor changes.