There are two inbound calls in the above scenario:
1. Creation of the Business Task in AC
2. Approval of Testing/Entry of test results once testing complete
Both of these calls would be web service calls to standard AC APIs (although alternative techniques are available and are described later in this document). The calling system (i.e. the ticketing system) would be responsible for queuing of messages and ensuring errors were dealt with appropriately. Some mapping may be required depending on the data passed from the ticketing system to AC for classification of the change.