"According to government rules, you cannot modify the e-invoice because it has already been uploaded to the portal as same invoice number,you need to cancel it first,
To cancel the voucher you can follow these steps:
Step 1:Go to the Transactions menu,
Step 2:Click on sales,and open it in modify mode,
Step 3:Give command CTRL + X,click ok,then specify Y to cancel on e invoice Portal also,give reason of cancel then click ok,the e invoice will be cancelled.
Then you have to generate new invoice again with the changes you want, with different invoice number,and e invoice generate again.
Further may be change date from your side manually by mistake or any reason.