I don't own it, SO I can't publish it. Any workarounds for this (Owner is on leave)

The Articulate staff might be able to help. You can contact them here: Contact Support for Help with Any Articulate E-Learning Course Development Software

For future reference, the Owner of a Rise course should assign at least one other team member as a Manager. A Manager can do more than a Collaborator, including publish the course. And, of course, before any team member goes on an extended leave or leaves the company, there should be a process to verify that they have transferred ownership of their courses.

Here is the User Guide info about collaborating in Rise: Collaborative Authoring in Rise 360 - E-Learning Heroes (articulate.com) 

Hi Prashanth! We are excited to share that we have released Rise 360 Team Folders! You can now create shared team folders in Rise 360 to organize your content and share content with collaborators even faster. We know this has been a popular feature request and we can't wait for you to finally check it out!

Your Rise 360 dashboard will look a little different, but don't worry. You can find all of your content, personal and shared, in the My View section. If you run into any snags or have additional questions about Rise 360 Team Folders, our team is available in this discussion or in a support case.