Credit card payment: How to erase "additional fees and interest" mistake entry ?

I wanted to pay the credit card and instead of writing the amount of the payment in the "Amount payment" section, I put it in the "additional fees and interest" section instead, the one just above. So instead of paying my credit card, I owe twice the balance now...I don't find a way to modify it directly. How can I fix that?

Thanks a lot!