Physical Move of Secondary Replica to a new Location
Is there anything that would need to be done on the secondary replica prior to shutdown.


I would suggest you to suspend data movement prior to the move (and resume it once the secondary server is up). This will have a side-effect of primary database accumulating the unsent transaction log records in the send queue. This means that for your maintenance time, transaction log on primary database cannot be truncated.

Remember that primary database is exposed - if it goes down, there will be data loss. Make sure you have a good tested full backup + T-log backups.


  Suspending an Always On primary database suspends data movement on all the corresponding secondary databases, and redundancy and failover capabilities cease for that database until the primary database is resumed.


You must remember to resume data movement once secondary database is online.

Also, depending on the database size (if its small), you can think of removing the database from AG and putting it back again once the move is successfully completed.