Cut parts from song and import them into the sampler on ipad

How do I cut parts of my song in garageband (ipad) and put them into the sampler to fix the pitch on specific parts of my pre-recorded vocals?

For example, I already have a song I recorded, and I would like to simply cut a few seconds of the vocals, go into the sampler, fix the pitch, and then re-insert the editied piece back into my song.

Is this possible on the ipad? I know that the "autotune" option isn't available on the ipad, but I simply want to fix the pitch on a few notes and I was wondering if there's any way to do that.

If there's not, do you have any suggestions or any app reccomendations that might help me achieve this? I can't afford a macbook pro so that's out of the question.

Sorry if my explination isn't clear! And thanks for any help :]