In sequence diagrams, you can move all message types on lifelines.
However, when you move a synchronous message with a return message, you must
move the send message and the return message separately and in a particular
order; otherwise, only one part of the message moves on the lifeline.
To move a synchronous message:
- Open a sequence diagram that contains multiple lifelines with at
least one synchronous message.
- In the interaction frame, click a synchronous message.
- Complete one of the following steps:
- To move the message up the lifeline, first drag the send message to
the new target location and then drag the return message.
- To move the message down the lifeline, first drag the return message
to the new location and then drag the send message.