jitendra,
Your question / post is interesting! 
Are you talking about debit memo? This as you know is a billing document. So are you saying create a billing document without creating a billing document.
Or are you talking about debit memo request? This as you know is a order.
You want to set the status of this order to complete without creating its (respective) billing document.
If you are talking about debit memo request and status complete without creating a billing document, I think this is not possible.
Could you please convey the business requirement behind this?