I am working on a virtual choir project and one of the singers has some different timing. I was looking for a way to stretch and manipulate the speed of certain sounds in Adobe Audition. It turns out, it is a simple thing to do. This tutorial taught me how, including special configurations.

https://helpx.adobe.com/audition/using/multitrack-clip-stretching.html

But the gist of this operation is to grab the white arrows in the upper corners and adjust the clip as needed.