You can modify WWN assignments for a virtual machine with an RDM.
Typically, you do not need to change existing WWN assignments on your virtual machine. In certain circumstances, for example, when manually assigned WWNs are causing conflicts on the SAN, you might need to change or remove WWNs.
Prerequisites
Make sure to power off the virtual machine if you want to edit the existing WWNs.
Before you begin, ensure that your SAN administrator has provisioned the storage LUN ACL to allow the virtual machine’s ESXi host to access it.