Gst reversals in thw subsequent period

Hi,

As per the audit thresholds 3% of errors are allowed and I made an error about making a wrong sales return entry and wrong purchase returns entry in thw last peruod.

I have overstated the purchase returns by 1000 over 50000 purchases and sales tax by 1000 over 50000 sales. 

What are the entries in the new period and how to claim extra tax paid? 

Txs.