Hi
If it's the CLI admin account that's locked, then the most common solution is to perform a password recovery (booting the VM/appliance from the .iso and choosing option 4). I say this is the most common solution, because in most cases users don't create a backup account that has the equivalent role as the CLI admin.
I didn't try to reproduce the admin account lockout in my lab, but I created an equal user called "arne" and locked him out.
ise01/admin# show user status
USERNAME ROLE DISABLED LOCKED
admin Admin
arne Admin *
If you had a backup account, then you could salvage the situation with
ise01/admin(config-password-policy)# no password-lock-enabled
That then clears the status of the locked account
ise01/admin# show users status
USERNAME ROLE DISABLED LOCKED
admin Admin
arne Admin
cheers
Arne