Managers to send custom notes/messages to their DRs when releasing their comp letters

The requirement is to have an option for a Manager to enter a personalized message/note for their direct reports when they release their compensation letters. Say if they want to thank them for their specific contributions during the year and so on. Is there any way that we can configure this?

Currently under the change statements setup, the statement delivery method is set to Centrally managed and stored allowing staggered release of statements. So Managers select the employee and release the letter without downloading/viewing it. They can see the letter directly under My Team Compensation section.

Thank you!