They only need to go to the QlikView Enterprise Management Console, System, Licenses, QlikView Server, QlikView Server License and click on "Upgrade from Server" button on the lower right part. The license number is usually the same, so it can be used only in one server. If the client wants a to change the Server to another computer, you will need to stop the other server, if you want to have them working fine. If you don't, one of them will show "Off Duty" in the QEMC, Status, Services tab.
Now he has the same Server but with Enterprise Edition license, not one SBE and one different EE.
Hope that helps.
The licence numbers of the SBE and EE are different. My client wants to know if it is possible to have the SBE on one server(for development purposes only) and the EE on a different server(for live purposes), as they would like to maintain two different servers.
Also, is it possible for the QV docs to be migrated from one server to another? Would copy-paste work?
If they are different codes, meaning if it's not an upgrade, but a new different license (not only the code), then yes, you can have two computers running two type of servers.
Documents can be copied from one server to the other, but there are some information I will not migrate but recreate, for example, reload tasks, document cal assignments and so. But yes, in short, copying the QVW file from one server to the other that will work, assuming all permissions and folders are set up all right.
Note that if you are going to have to QlikView WebServers, by default they listen to port 80. That's not a problem in the local network when you type the url, but if both servers are behind a firewall, or you use some NAT rules, you may need to change the port so they don't conflict. Check with your IT people.
Hope that helps.