VMware converting RAW disk to VMDK

Convert a Vmware RDM disk to VMDK while guest VM is powered off
Power down the guest VM

Clone the VM, under select virtual disk format – select Advanced – change the disk format to Thick provisioned. You only need to do this step for the RDM disk. Completed the steps to create the clone, the RDM will be converted to VMDK.

Convert RDM to VMDK using storage vMotion
Power down the guest VM to convert the RAW disk from Physical compatibility mode to Virtual compatibility mode. Skip this step if already in Virtual mode.

Edit the settings and remove the RAW disk. Select remove from virtual machine and delete files from disk.
Add RAW disk back with virtual compatibility mode. Click on Add disk – RAW device mappings – select RAW disk – store with virtual machine – virtual compatibility mode.

Power on the VM. Now you can storage vMotion the VM while it is powered on, this minimizes the down time. Right click VM – Migrate – change datastore – advance – disk format is Thick.