This is probably too obvious to mention, but you can, of course, bounce the whole vocal to another track and use Transpose Audio
 

The one from ToneBoosters works well.

ebibault51
The one from ToneBoosters works well.

Great plugin for monophonic material. But if you need to transpose polyphonic source like guitar strumming, you'll get glitchy sound. Sonar's Process->Transpose sounds better. But it's off-line, destructive and has no formant scaling. Nothing's perfect.

paulo

Kamikaze
The forments aren't changed in this though, it's just slowed, and so a lower pitch. Changing the formants would do the same without slowing the track or changing the pitch. You can do the same in Sonar
 
The slowed record version that sparked that has the same effect

Yes, I am aware that this is just a standard speed change simulating 45rpm played at 33.3rpm. The OP was asking about pitch shifters - I was simply making the point that Audacity is a useful tool that can do this as well as many other things.

Known fact that Dolly's voice was misformanted at birth, so any pitch shifting will only serve to make her sound.... "normal".

Soundwise
While we are at it, Sonar Platinum should have Formant Scaling, but this option is grayed out. Any reasonable explanation why it doesn't work, or it's a bug?
 

 

This needs to be fixed, like, right now...

OK. A little more googling and the answer is HERE. If you use 32 bit Sonar it will miraculously appear.
 
After trying it in 32 bit Sonar, it doesn't seem to work so great. All I get is a muffling effect @-2.00 and increased high freqs @2.00 with no discernable change in formant, making it unusable at my end.

The different transpose capabilities 32 and 64bit SONAR have been around as long as 64bit SONAR.