We will change the SCAN LISTENER Port from 1522 to 152

1. Check the current scan listener configuration.

$ srvctl config scan_listener

2. Modify the scan listener to use new port 1523.

$ srvctl modify scan_listener -p 1523

3. Restart the scan listener.

$GRID_HOME/bin/srvctl stop scan_listener
$GRID_HOME/bin/srvctl start scan_listener

4. Update remote_listener parameter in database.

SQL> Show Parameter remote_listener
NAME            TYPE  VALUE
--------------- ------ --------------------------
remote_listener string racdb-scan.orcl.com:1522

SQL> Alter system set remote_listener='racdb-scan.orcl.com:1523' scope=both sid='*';

5. Conform the changes:

$GRID_HOME/bin/srvctl config scan_listener