How can I select a server in system-config-printer?

The server dialog in the Linux administration tool system-config-printer looks like this:

However, the CUPS server may not be on localhost but on a remote machine. How can one tell system-config-printer this? The input field is fixed and does not allow any changes. Is there a configuration file that could help?

What you see is system-config-printer v1.5.7 on Lubuntu 16.04.