In Sonar Platinum, I tried to Punch in a few words in a vocal track which had been Melodyne treated using the Overwrite option, hoping to replace the previously recorded part,  However it kept the previous part without deleting it, so I am hearing two voices.  I am wondering if this is because I had used Melodyne on the track.
 
If this is so, what is the best way to replace part of a vocal if you have applied Melodyne to the track?  Thanks.

1.  Did you render the Melodyne audio track?  If not, there are many functions that can't be performed on it.  I assume a punch-in is one of them.,
 
2.  Did you look in the take lanes to see if there is indeed a new and an old take?  If so, mute the old melodyne one you don't want and listen to the new one.
 
3.  If it didn'r record, just record on a new track and cut/paste it into the old file later.  Use a clip envelope to silence the part of the old track you dont want to hear during recording.