You can change the connection properties of an existing repository location.
To change the properties of a CVS repository location:
CVS Repository Exploring perspective or add the
CVS Repositories view to the current perspective.Note: The properties will be changed for all projects shared with the selected repository location.

Team programming with CVS
CVS Repositories

Creating a CVS repository location
Changing the sharing of a Project
Changing the encoding of a CVS repository location