The NSX-T Manager VIP can be removed via the API.
Validate your VIP with the API call below.
GET https://NSX-Manager-IP/api/v1/cluster/api-virtual-ip
Delete the VIP with the API call below.
POST https://NSX-Manager-IP/api/v1/cluster/api-virtual-ip?action=clear_virtual_ip
Set a new VIP with the API call below.
POST https://NSX-Manager-IP/api/v1/cluster/api-virtual-ip?action=set_virtual_ip&ip_address=(your VIP ip here)