I am running a primary and replica Authentication Manager, each a VM, currently at version 8.1 SP1 P09. What is the appropriate method for upgrading both to version 8.2 SP1 P04? I would like to keep one active at all times to avoid a blackout in user authentications. I know that administrators will not be able to make changes, such as add, enable, or disable tokens during at least part of the upgrade, but that is acceptable.