How do i delete voice with Sony vegas studio platinum?

I have recorded a movie and uploaded it to sony vegas studio, and the voice recorded with it has also been uploaded. For certain parts of the movie i want to delete the voice, and add voice overs or captions.When i click he voice and split and delete it, it also deletes the part of the movie is is coming from. Is there anyway to delete the voice in that certain section or mute it?

For each clip theres a video and audio, click the audio bar under the visual and drag it down to another level, not the same level where your music is coming from (assuming you have music in your video) and then look to the left and the box has a volume bar just slide the bar all the way to the left to mute it, Hope that Helps! BTW, do you know how to speed up clips? i know how to slow them down but i dont know how to make them go fast… so if you know, Please tell me! tia