Ok, here is what I have. Client setup DAG and it has worked flawlessly for quite some time. Unfortunately they weren't paying attention to the File Share Witness server and it crashed (the DAG didn't give any warnings, it just kept working). It was setup on a Hyper-V machine and the physical machine actually crashed and since they didn't realize that the File Share Witness was on it, they simply wiped the machine and set it back up without the File Share Witness. Now, I am tasked with fixing this.
Here are my thoughts. They have two servers on site and one offsite. All three are replicating to each other successfully. My idea was to make one server the primary one with all the mailboxes active on it. They remove the other two servers from the group, one at a time, and then remove the DAG service. Restart the primary server and create the FSW back on the old Hyper-V. Setup all the permissions as before and then add the DAG service to the Primary Exchange server and then add the other two servers back.
Sounds good to anyone? Is that all the right steps as far as you can tell?