For the pitch change, if you get the audio and open it up, (double click). Then highlight the bit you want to slow down and right click process. There should be a pitchshifter effect. In that there is a way of shifting the pitch at a gradient, so that it starts normal and finishes, however many semitones you tell it, lower.
Then if you want you can time stretch it to give the effect of slowing down. Perhaps if you cut it up into bits and time stretch each bit in stages, streching out the end more than the beginning.