Your client can access their Favorite Lists at any time simply by clicking on the heart icon at the top right corner when viewing their Gallery.
If they have been logged out of their session, they may need to re-enter the email address that they used to create the Favorite List.
After logging in, they will see all of the Favorite Lists created under that email address, and they can then click into a list to view the images.
From here, clients can Share, Download, or Add Notes to the images, if these options are enabled.