Export backdated updated vouchers using Http XML Request from C# application

I have exported all vouchers from Tally in database using HTTP XML Request using C# application.

I have one question,
- Suppose Tally has vouchers from "01 Jan 2017" to "01 Feb 2017"
- I have exported all those vouchers
- If Tally operator update voucher created on "02 Jan 2017"
- Then how I can find/export backdated vouchers which are updated on specific date (say "09 Feb 2017") using XML request.

Thanks in Advance