Networking And Gateways :: Changing Of Listener Port Number?

i have a listener configured on default port 1521 and i wanted to change it. i did following:-

1. stop the listener through lsnrctl stop

2.change the port number in tnsnames.ora and listener.ora and save both files.

3.now i start the listener as lsnrctl start

4.it started successfully but saying that it cannot register to instance.

5.i connect sqlplus / as sysdba and execute "Alter system register" and "System Altered"

but even then the listener is not registering.