The same use case and activity notations applied to a fresh scenario, so you can see the method again, end to end.
Scenario. Customers raise support tickets. A support agent works each ticket: they always check the knowledge base first and always notify the customer of the outcome through an external notification service. Hard ("complex") tickets are escalated to a senior agent, who is a more capable kind of support agent. The system also lets agents follow tickets through to closure.
Use case diagram
Built from the scenario: actors, use cases, include, extend, a secondary actor, and actor generalisation.
Activity diagram
The Resolve ticket flow across three swimlanes, with a decision, a merge, and an external hand-off.