The handover feature is still in planning and development. It is not yet released.
Words from the Creator of Jade:
As of Sep 2015, my kid is 1 month only. I foresee I won't be handing over her the journal until she is at least 6 years old. While I personally don't need the feature yet, we will definitely develop it. Vote for this feature, and we could help push this out sooner.