How to change size of bezier open line

If someone know, please advise me.
It is very simple. I make open bezier line, and want to re-size the line shape.
Other drawing software, when click the line, out line box appeared and change size by dragging box.

Thank you for your help in advance.

I see two possibilities to achieve this: 1) If you know the overall size of the bounding box (which is not visible in OmniGraffle for a line object) of the line, you can enter it in the size box above the ruler. 2) Make a small dummy object above the line, select line and dummy and group these two objects. Selecting the group now shows the bounding box and you can drag as desired. If the size is ok, ungroup and delete the small dummy object.

Thank you for your reply.
OK, I’ll use option2), make dummy bounding box.

Best regards,