Rename SCAN Port in Cluster:

Login as grid user, source the grid environment.
Make sure $GRID_HOME/bin is in PATH.

1. Modify SCAN listener port:

[grid@rac1 ~]$ srvctl modify scan_listener -p 1523

2. Restart SCAN listener to be effective of new port:

[grid@rac1 ~]$ srvctl stop scan_listener
[grid@rac1 ~]$ srvctl start scan_listener

3. Verify the change:

[grid@rac1 ~]$ srvctl config scan_listener
SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1523