1) Open a shirt 2) Prepare to remove a middy 3) Prepare to take off 4) Undo 5) Undo the buttons of 6) Unfasten or undo 1) Undo 2) Unfasten 
• (v. t.) To loose the buttons of; to unfasten.
[v] - undo the buttons of
to free (buttons) from buttonholes; unfasten or undo. · to unfasten by or as if by unbuttoning: to unbutton a jacket. · to disclose (one's feelings, thoughts, etc.) after deliberate or prolonged silence.