Hi!
Actually 1941 is a router, not a switch.
If I understood your question correct, so:
Router>en
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#hostn
Router(config)#hostname 123
123(config)#^Z
123#
%SYS-5-CONFIG_I: Configured from console by console
