Accidently discarded line for the paid invoice.

Hi,

The user accidently discarded line by clicking on "Discard Line 1" of the  already paid invoice. The invoice is only having one line so the invoice shows zero amount at the line level.

The invoice now shows as not validated.

How do I make it so it goes back to same status?

I have to create new lines for the same amount and validate it?

Do I have to void the payment as it was alrady paid and cashed by vendor?

Thanks,

Nishank