Hi Ken-9235,
Where is the Quorum? If you have two nodes and disk witness (or file share witness) in primary data center A, and the whole site
goes down, you will need to force the start of the cluster on the remaining node in your DR site because you have lost too much at one time.
You can change the availability mode of the secondary replica SQL06P on the site B from asynchronous to synchronous with manual failover or automatic failover, do a failover from the primary data center to remote data center before shutting down the primary data center.
Best Regards,
Amelia