The issue you are seeing is that to be able to have Repository on another node from the Primary, you need to be able to bring the cluster up with 2 copies of the repository (Active / Passive), and let Tableau Server replicate the data from one to the other, when the cluster is started.
Once the Repos are in synch, you can then shutdown the cluster, and remove the repository from the primary node.
However, to be able to have Active / Passive Repositories (on 10.x) you need to have at least 3 nodes in a cluster!!
My suggestion would be; are you able to add (temporarily) an additional node. You only need to have (say) the Gateway process running on it, (so it doesnt count towards core licensing)
This will fulfill the requirements, and let you 'move' the repository.
Once, done, you can remove the additional node, and should have your end state.
Hope this helps
What exact version of Tableau Server are you using? 10.1.?