UI only shows the initial name configured for the Tier-0. To make this change it is required to edit the VMware Cloud Director DB.
VMware Cloud Director 10.x
NSX
UI only shows initial Name for Tier-0 in the Provider Gateway Configuration Page
This will need the modification in the VMware Cloud Director DB, so please make sure to take the backup of the VMware Cloud Director Database: Backup and Restore of VMware Cloud Director Appliance: LINK.
Please open a case with Broadcom Support to do the modification in VCD Database. For more information, see Creating and managing Broadcom support cases