I need dialogue removed so that we can add in our own dialogue instead into an animation video. Is this possible to do with audition? Or any other program maybe if you know of one that exists?
If the dialogue is panned centre while everything else is stereo and if there's not a lot of reverb etc. then have a play with the Centre Channel Extrctor. It does as good a job as any software out there and better than most--but, as you can see it's a pretty "iffy" process.
FYI, the more normal way to do this is as the supplier of the animation for audio stems without the voices. The company I worked for bought rights to various European animations on a number of occasions and this is how we got what we needed.
The other way (since it's animation) is to simply start from scratch and build your own music and effects.