What should I do if I uncover new evidence on a question that I answered that invalidates my previous answer?

Question

I recently answered Is “US Military Intelligence report EW-Pa 128” real? with some information from a forum post. The evidence wasn't great, and I fully admitted it in the answer. However, given the challenge of proving the non-existence of a document that seemed like it was made up for a fictional narrative, it was the best I could do at the time.

After performing some additional research days later, I have uncovered clear that the document is most likely real (although not to say it's accurate). How should I proceed in this case?

• Edit the original answer, completely wiping out the old information and leaving only new infomation

  • Pros: only accurate information available, cleans up what turned out to be a bad answer
  • Cons: removes the answer that other users upvoted, makes it impossible to see the old answer without going into edit history
• Edit the original answer, leaving the old data but in an "archived" state
  • Pros: leaves old information available, still gets good information out there
  • Cons: answer becomes a mess
• Delete the original answer and put the new answer in
  • Pros: same as first option but also eliminates upvotes
  • Cons: same as first option but even harder to see original information
• Leave the original answer and answer again
  • Pros: leaves old information available, gets good information out, original answer isn't a mess
  • Cons: karma farming

What's the best course of action?

Answer 1

The 4th option makes the most sense to me.

Leave the original answer and answer again

It is possible to answer the same question multiple times, and from the sounds of it, you are providing two completely different answers.

They both rely on different evidence, and you even admit in your first answer that the evidence for it is weak. It seems beneficial to leave both around, as people did find the admittedly weak evidence useful.

Cons: karma farming

I don't really see this as a con here either. You provided one answer with the best information at the time, and people should have judged it based on it's merit, so deleting it doesn't make much sense. Now you've found a different answer, which should also be judged based on it's merit; so editing the other answer to be the new answer doesn't make much sense.

It may also make sense to edit a note into your first answer, explaining that you found better evidence and posted it in another answer.

Option 2 could also be a good choice.

Edit the original answer, leaving the old data but in an "archived" state

Given the length of your existing answer though, I think that adding a second answer onto it may be excessive, which is why I think option 4 makes the most sense to me.