GST liability

shikha (student) (73 Points)

09 January 2020  
I filed gst1 on 10th of the month.On 12th I realised the sale was shown more.I cannot rectify now as gst1 already filed. But can I pay less gst based on revised calculation on or before 20, and file GST 3b? and then pass the credit note in the next month?