There's some fun instructions on how to manually do this, but, what I've found the easiest is to have a second witness appliance in the environment and move the cluster to the new witness when a network partition occurs. Unfortunately I have two sites that have some pretty bad WAN links and have to do this at least once a week, where I'm moving clusters between my two witness appliances to resolve the cluster partition. I had one cluster also do this after a cluster shutdown, and it was due to a DNS issue where the hosts could not perform a DNS lookup for the witness appliance because I set the hosts primary DNS to a VM in that cluster. That was pure PEBKAC, but, the resolution was the same, transfer to the other witness appliance and all was happy again.
Having the second appliance is also nice if you have multiple 2-node clusters and want to do a full stack shutdown because the wizard will shut down the witness appliance for the cluster as well, so being able to have the cluster being shutdown on it's own appliance and then have the others on a separate one is absolutely a requirement in my book.
