You can send messages and requests to yourself to act as reminders to do things.
For example, to send a reminder to continue working on a document or notebook entry, click on the ‘Messaging’ button from the document view. You can then send a ‘review record’ request to yourself with a time/date that you can subsequently download to your calendar app as a .ics file.
You can then manage this request in the same way as any other – just remembering that you are both the sender and the recipient! So, as the sender, you can Cancel the request from the SentMessages section of the Messaging tab, and as the Recipient you can set as completed once you’re done.