If I change the SID as ORAL , then what will happen to ORCL sid. ?

I have to connect to both the database in the same machine. In that ORCL and ORAL are the respective SID's.

In my Listener.ora entry for ORCL is there and it is getting connected. But no entry for ORAL. How to make entry for ORAL in the same Listener.ora file ?


Thanks
Ravi