For example, if you have a composite class view in one sequence diagram and want to navigate to its parts, you can click the composite class and open a collaboration, which shows how its internal parts communicate for a particular scenario.
Part decomposition is a specialization of an interaction occurrence.
In the sequence diagram, the name of the reference sequence diagram is added to the classifier role label (after the word "ref"), as shown in this example.

As with other interaction occurrences, navigate to the reference sequence diagram by right-clicking the instance line and selecting Open Reference Sequence Diagram.