GSTR-2A

if the ITC in 3B is more than in 2A, then you have to reverse the ITC and also pay interest.

if less , then?

how to reverse itc

As per section 16 , to have ITC claim : 1.Have Tax Invoice
2.Reced Goods
3.GST has been Deposited by Supplier
4. Further of business

So As per point 3 can only be achived if GSTR1, 2,&3 all had been filed but its was not. Hence nobody knows whether your supplier has deposited the GST on the bill raise to you . iam not denying the bills reflected in 2a has no importance in claiming ITC, but ... if you have reced bill & reced goods & the same is not reflected in 2a you still liable to claim ITC .

In short Any difference in 2a with your books can be match by increasing or decreasing ITC in your 3b & keep prepare reco. statement for the same

@ Mohit Lodhi.,

(if less , then?) then You can claim the ITC in Your next return (You can't avail after September-18 GSTR 3B return)...

@ Vishal Goel.,

(how to reverse itc) You ll add to Your outward value which is wrongly claimed ITC in any of the previous month/s and Pay interest @ 24%. Interest will be payable from the ITC availed date.