How can we correct wrongly submitted gstr1

Further -- I have One more Doubt ...

The Gst Portal should show an error when Table 12 is left Blank 

But , no error popped up and the return was submitted without hsn Details 

Dear Mahesh.,

You can't revised any returns in GST...

In case your T/O is less than 1.5Cr in PY then you don't be worry for blank in HSN Summary...

In case your T/O is Above 1.5Cr in PY you ll must at HSN Summary. If you leaved it. But, The system is support your return also the AO ll be give any rectification. I don't be confirm it. But, May be GSTN ll be  leave it...

So, wait and see