The Edit option to change/replace Usage Meter Serial Key is grayed out :
Usage Meter 4.8.x
Editing the License Key in the Usage Meter UI is not allowed as per below explanation :
After the transition to the new Broadcom Advantage Partner Program, vCloud Usage Meter automatically collects the license keys
vCloud Usage Meter sends the information about the license keys to Broadcom Support Portal and Broadcom Support Portal classifies the license key in the following categories.
Reference Document : https://docs.vmware.com/en/vCloud-Usage-Meter/4.8/Deployment-and-Administration/GUID-6CF4F902-083F-4CFF-ACE1-26289512E5D3.html