Thanks guys I will give this a go when my change window opens later this afternoon 
We are introducnig a VNX Gateway to run from our VMAX.  To ensure there are resilient paths across 2 engines (right now I only have free paths on the same engine) I have removed a port from an existing port group that was providing 4 paths to an ESX farm reducing this to 3 available paths. I then want to clear away the devices previously presented to the ESX farm so I have a clear set of addresses for the VNX storage to be mapped to.  When I removed the port from the port group i did not unmap at the same time. If i use a symconfigure command to unmap I am told I need to write disable the device which I cannot do as it is being actively used on the ESX farm still via a different port.  Is there away of getting around this issue without having to migrate running vmware guests from a datastore before I write disable and then unmap?  Help would be appreciated.  thanks
Is it possible to unmap a device without write disabling the device?