How can others in my team access material stored in Rise?

Hello,

I belong to a team of instructional designers who are responsible for creating and maintaining course content in Rise 360. Some of the course content has been created in Storyline 360 and imported into Rise via Review 360.

We have recently had someone join our team.  They are unable to view the material that was previously published in Review 360 and cannot update the associated course, even though they have been assigned as the Course Owner.  We want them to be able to update the Storyline 360 content by replacing the existing file in Rise 360, but they can only seem to create new content, not replace existing content. 

What do we need to do to give them access to existing material in Review 360?