Hello Ram,
What I think you want to do can be achieved if you are using Sharepoint Designer for your workflow. Create a promoted property to hold the approval status on your form. If you need the workflow to fire when the state of the form is "approved" and not "submitted," make the property default to Submitted when the form is submittedand have the workflow only fire when the status is changed to Approved. Hope this helps!
Janice Thorne Microsoft Certified Professional
Qdabra / Streamline data gathering to turn process into knowledge