How To Modify SCAN of CRS(Grid Infrastructure)

 Requirement:

    We re-purpose a 12c RAC Cluster for a new Application. We need to update CRS scan name to reflect new name.
    Old scan name:  oldapps- r
    New scan name: newapps-r

Solution:

 In OS,  nslookup newapps-r   --- to make sure scan is registered in DNS

Stop scan listener:
$GI_HOME/bin/srvctl stop scan_listener
$GI_HOME/bin/srvctl stop scan

Modification:
as root
$GI_HOME/bin/srvctl modify scan -n newapps-r
$GI_HOME/bin/crsctl modify type ora.scan_vip.type -attr "ATTRIBUTE=SCAN_NAME,DEFAULT_VALUE=newapps-r" -unsupported
       --------------- must add -unsupported flag to bypass check.  see Note: 1918102.1
Start scan:
$GI_HOME/bin/srvctl start scan_listener
$GI_HOME/bin/srvctl config scan