When creating a new virtual machine, select Mac OS X as the operating system. If you don't know how to do it, read the NetBoot documentation from Apple first. To NetBoot an OS X virtual machine, the following requirements must be met:
Using this functionality, you can boot a virtual machine from a network and install (or reinstall) a desired version of OS X on it.
Parallels Desktop Enterprise provides NetBoot support for OS X virtual machines. NetBoot is a technology from Apple that allows to boot a Mac computer from a network. NetBoot Support for OS X Virtual Machines