Move VMDKs to a another VM

Hi

Here is the situation:

I have a Windows Server 2003 Server that I need to decommission and move the disks to a Windows Server 2016. In order to move the disk, i need to offline the disks and detach them from the source vm.  The problem that i have is the the offline option is not available in 2003 under Disk Management.

What would it be the best way to move the disk to the new vm?  do I need to shutdown the server and remove the disk that way? or there is a way to take the drives offline on a power on state vm?

I tried diskpart but it does not work to take the drives offline.

Thanks in advance.