Build process without deleting pre-install VM system

We have some people who want to use Packer on a VMware vCenter environment to build from ISO. Due to policy restrictions they do not have the permissions to create or delete actual VMs but items such as power on, power off, etc are granted.

Is there a method in Packer to start with an existing powered on or powered off VM, skip the delete phase, and then use that existing VM for the remainder of the build process?