Hi Suriya ,
You need to:
1) First create a "User Decision" step in ur workflow template , add 2 decisions "Reset" and "Reject" .
2) You can then capture the user decision and taking appropriate action on ur object (PR) .
For which you can create a standard task - type "Background" , link the task to your BO object methof and call the required API's for ur object(PR)
Add a statement for Call transaction in the same BO method to open the respective tcode.
Hope it helps.
Best Reards,
Rini