You can remove a subcustomer
If you no longer need a subcustomer you've previously registered, you can use an API operation to remove it.
This is accomplished by running the "Remove a subcustomer" operation via the ACE API. You'll need the following values to run this operation:
propertyId: This is the unique ID value associated with the base configuration that houses the target subcustomer. Contact your Account Representative for this value.
sub-customerId: The ID associated with the subcustomer you want to remove.
network: You need to decide which network version of the subcustomer you want to remove: production (live) or staging (testing).
See the ACE API docs
Call formatting and specifics are covered in the API documentation: