To copy models from one tenant to another you'll need to get firstname.lastname@example.org involved. Here's a checklist of things that will need to be in place though:
No proprietary data
The workspace ID from both tenants. You can see that in the URL when you're logged in
The source Model ID
The support person at Anaplan may ask you to give them temporary access to the workspace. With CIM (central identity management) you may have to get someone with user admin access, usually the tenant admin, to add the name.
Copying from one workspace to another within the same tenant is something you can do. Just go to "manage models" and copy the model.