I have a file that I currently own, and it is shared with someone else. Is there a way for me to change ownership so that this other person is the owner? Or to make it so we are both owners? Either one would be good.

HI Megan, I know you said you had no access to changing over the ownership.  You can share the project with your team member and they can make a copy and be the owner. But the both of you can not own the project together.