In sequence diagrams, you can remove interaction operands from
combined fragments that contain multiple interaction operands. Otherwise,
you must delete entire combined fragments to remove interaction operands.
You must have a sequence diagram with lifelines and combined fragments
open.
To remove an interaction operand from a combined fragment, in the
diagram editor, right-click an interaction operand; then click .
The interaction operand is removed from the combined fragment, and
all messages and interaction fragments that the interaction operand contains
are also deleted.