Slow motion

yes. Pull up the slo mo video and you should see a timeline at the top of the video. Underneath it you should see a blue slider bar which allows you to decide when the slo mo starts and stops.

 

Just tap the Slow Motion button again. It should work. I've done it.

 

I think you want to slow-mo two different parts within same video ... I believe that functionality is not there within the photos app ... you can only select one portion in a single video

You can use other 3rd party apps or iMovie to post process and alter multiple portions though

 

Use iMovie, it's free for iPhone 5S buyers.