Most “audio editing” software will do this.
“Peak DV” is a program that came bundled along with FCP 2 & 3 (and I think, FCP 4).
It has a function under the “DSP” menu called “Duration” that will do what you want.
You import the original track and change the duration to a new length.
But beware, use it sparingly, and don’t expect miracles.
You can only do this by a VERY SMALL percentage (5-10%?) before it becomes apparent that something “sounds funny”.
Nothing beats a properly-recorded (or re-recorded) VO for the best quality.