Locking the database to a single user so that other user wont change it

I am using SQL Server CE 4.0. In office the database (.sdf) file are on a server. When I want to change design of the database I have to copy it to local PC and access it since n/w connection to a compact database not allowed.

But when I modify the design of tables I have to be sure that no other user in my office connects to that database and changes the same database. Because I have to again copy the changed database to my server PC and I don't want the design changes made by others. So how can I be sure that no one else connected to the database which I have been editing. Is there any method of locking the database to a single user when I edit the design of the database.