PFManager can release entitlements that have been assigned to the host it is running on. Entitlements that have been assigned to another host must be released by a PFManager instance running on that host. PFManager cannot release entitlements remotely.
If a machine can no longer be accessed in order to run PFManager (for example is the machine is broken and will not boot up) you can log into the PFAccount Admin portal and release the entitlement from there so it can be assigned to another machine.
Please note: Releasing an entitlement using the PFAccount Admin portal in this way will mean that machine can no longer be used to run software from The Pixel Farm. This is final and cannot be undone if that machine becomes available for use again.