Why do you need to send an attachment back without having done anything to it?

You can probably drag-and-drop the attachment from one message to the other. But it's such a weird thing to do I don't know if I have ever tried it.

Some reasons might be: cannot open attachment and would like the sender to check if it's corrupted which is my current situation. Or send to everyone on the original email and add others to the email with questions, etc.

"cannot open attachment and would like the sender to check if it's corrupted" - I think I'd attach the whole incoming message if I was concerned about corruption. Then the sender would see exactly what you received.

If it really is damaged it's quite likely you won't be able to process it meaningfully, anyway. Saving it or my suggestion for drag-and-drop may just compound the failure. :-(

"send to everyone on the original email and add others" - you think all those who have already received it would want a second copy? ;-)

What error did you get with the original attachment? What kind of document was it?

Our work flow requires this too. I did a google search and found lots of people responding that "you don't need to do that". We get a ton of emails transferring, and it saves a lot of time to just get the attachment with the answer. So yes, we do need to do that. Now the question is, is there a way to accomplish this?

I'd probably used the Mail Redirect add-on if I got a message that would be more appropriately handled by someone else.

If it were important to signal to the recipient that i had redirected it to go them, I'd just forward the original message as an attachment. You can drag and drop any message onto another to attach it.

I think you should ask whoever designed the workflow how they expected you to do it.