How can I allow requesters to view Change Requests they are assigned to, in the Service Portal?

I know they can see Service Catalog items and their open Incidents, but they don't appear to be able to see any open Change Requests they are the Requester for, from the customer portal.

It looks like they can access the request using a hyperlink to the Change Request if they have permissions to View Changes, but I don't see how they could access this without being sent the link.

Thanks in advance!