In Melodyne you use the format tool to change the timbre of notes. You might be able to get something close to the original timbre, however 6 half tones is a lot jump so you may run into other artifacts.

But the real question is how good is your friends hearing? The reason I ask is because even though you can move notes around they will not sound exactly like the original note. Each note has a specific set of harmonics/formats. When you move a note those harmonics/formats move the same amount as the original note while the destination note will have a different set of harmonics/formats.

BUT only a few people will be able to tell the difference. I worked with a guy whos daughter sang a wrong note so I moved it to the right note one step higher. He could tell that wasn't sounding right; he had no idea what I was doing while using Medodyne. Personally I can not tell the difference.

My goal this weekend is to move just enough each day so that no one pokes me to see if I'm dead or not.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware