Can you rebase a course to another? Like git rebase stage to master.

[manilpit]

Can you rebase a course to another? Like git rebase stage to master.

We have 30 courses in which we have had a "stage"/"qa" course and a "prod" course. 

However people have directly made changes in the "prod" course. 
Now we need to totally revamp all 30 courses due to a design upgrade. And if we use the old "stage/qa" courses they are not updated versions. 

How can we update all "stage/qa" courses to be up to date with "prod" courses, then edit all "stage/qa! courses to the new design. Then finally import the courses back to "prod" and not lose students history?

This affects around 10000 users of ours. 

We have tried import export, we have tried bluecourses but nothing seems to work right. 

The original "stage/qa" to prod works fine. However upgrading "stage/qa" manually to be similar as "prod" is a massive job.