you can install QlikView Desktop in the machine where QV Server is installed. You can use Personal edition in this server to create and edit applications (qvws). However is important to note that you won't be able to edit documents created in other computers,
Other than this, you'll need a Named Cal in order to open any qvw in QV Desktop and edit them,
Document CALs are managed by the server and are assigned to documents by the server. So they are not actually on the document. It is fine to overwrite the file, the CALs will not be affected. You can even create a new document and replace it and the CALs will still be there.
Editing the document on your local PC and overwrite the one on the server is completely fine.