Cross-link with student submissions

Community Novice

I need to cross-link a teachers courses AFTER students have already submitted assignments. I tried course export, but now its saying I don't have permissions to access the link of the export. I am set as a designer on this course. Thank you for your help! Also, if I've already cross-listed and may have lost student work, is there a way to get it back? I'm afraid I already know the answer to that one...