What is your Oracle Version?
After the failover, how can you reconfigure your standby? what is your method? such as flashback,recreate standby etc.
You can use the below link, but you should decide about the above questions,
I have environment where one primary and two standby database is running in production. I need your help and guidelines to simulate the failover to one of the standby without shutting down the Primary.
Thanks & Regards
Welcome to the Oracle Forums!
Why simulate failover? If you want check you data guard configuration and application continuity, then you must perform switchover to a standby database for all tests.
and you wrote without shutting down the Primary. It means you don't want stop database (in other words stop application).
For this you must configure client failover for you Data Guard Configuration (add service and configure DB_ROLE_CHANGE trigger) and Application client connection settings.
If you say no, I want performe FAILOVER to standby, then my suggestion enable Flashback for reinstatement old primary to new standby before failover.
Don't forget in this case, primary database will shutdown.
Mahir M. Quluzade