[tryton] data move from draft state into approved state

[dineshkumar]

hi,

           I am developing the pharmacy module for the hospital management 
system.. I created the buttons such as draft,approved and pay..
           if I click on the draft button,then The data will be showed in 
the draft state.
           if I click on the approved button, then the data will be moved 
into the approved state.

          what is the solution??