Is there a way to save a VM while terminating the VM subscription?
Virtual Machines are removed along with their subscriptions, so there is no such option.
As a possible workaround, the VM can be cloned with the prlctl command. Cloned VM can be renamed if necessary. In this case the IP address of the cloned VM should be added to OBAS IP pool exclusions in order to prevent OBAS from reassigning the address to another subscription.