How to correct a inadvertent mistake in the gst return

The sales amount in the GSTt return has been inadvertently shown as one zero less than actual . But the CGST & SGST amount has been correctly calculated on actual sales and shown in the return. For e.g. The actual sales is 1cr but in the return it was wrongly input as 10lacs however the GST is calculated on 1cr and shown in the return.. Please advise how to correct this mistake .