Change default listener(name and port) to new listener in oracle 11g

1. create new listener using netca with different name and different port.

2. add the below in tnsname.ora file

listening_endpoint_1531 = (ADDRESS = (PROTOCOL = TCP)(HOST = dbname.domain.com)(PORT = 1531))

3. stop and start the listener.

4. login to database

SQL>conn /as sysdba


NOTE:But how will the instance know where the listener is located? 
You have to tell instance where listener is located manually by setting the LOCAL_LISTENER parameter.

SQL>alter system set LOCAL_LISTENER='listening_endpoint_1531' scope=both;

Now your instance is aware of location of the listener that is running.
But it may take up to 60 seconds for PMON process to carry instance information to the listener.
If you want this to happen immediately you can manually trigger service registration.

SQL> alter system register ;