Architecting and designing : UML 2.0 Lite : UML models : UML Sequence diagram : Synchronizing sequence diagram with collaboration diagram
  
Synchronizing sequence diagram with collaboration diagram
To synchronize a Sequence diagram with its partner Collaboration diagram, select Draw > Synchronize Diagram from the menu.
If you have a Sequence diagram open and in focus, selecting this command will change the partner Collaboration diagram so that it reflects the same information as the currently open Sequence diagram.
If you have a Collaboration diagram open and in focus, selecting this command changes the partner Sequence diagram so that it reflects the same information as the currently open Collaboration diagram.
See also
UML Sequence diagram