I submitted my return via efile, found an error that reduces the balance due, if I was mailing the payment on the orig can I just send the fixed tax, the 1040X with the $

I am trying to understand the sequence.  The example is this:

1.  I owe $1000 on the original that was efiled

2.  The 1040X reduces the amount due by $200

3.  I have not mailed the check for the original, do I just send $800 or do I send the original balance with a 1040V then submit the amendment for a refund?