Terminating participants in interactions by using stop nodes
In sequence diagrams, you can add a stop node to a lifeline
to represent the termination of a participant in an interaction. You
can only delete a stop node that you created manually.
Creating stop nodes
In sequence diagrams, when you create a destroy message, a stop node is created automatically. However, you can manually create a stop node on a lifeline to terminate a participant in an interaction. The lifeline ends at the stop node, which is designated by an X.