And that is the same storage where machine is already.
As viewtopic.php?f=35&t=55003 says:
VirtualBox v6.x has made it easier still to move a registered VM around on a single host: just right click the VM in the manager and select "Move...". If for some reason the built in feature isn't suitable (e.g. the VM not registered), or if you want to move the VM to a different host then read on, as the v4 method (a.k.a. Manual Method) still works...