Each create, update, or delete request must use a unique change token.
If your application submits a GetChangeToken request and then submits
a second GetChangeToken request before submitting a create, update, or
delete request, the second GetChangeToken request returns the same
value as the first GetChangeToken request.
When you use a change token in a create, update, or delete request, the
status of the change token changes to PENDING, which indicates that
AWS WAF is propagating the change to all AWS WAF servers. Use
GetChangeTokenStatus to determine the status of your change token.