How to end an apprenticeship?

stoneship

I know it's a noob question but still. 

I have an apprentice in game with the game system. And I want to switch it to another player. But I can't find the way to do so. Will anyone be so kind to explain to me how to change it?
Thank you.

Phoenix1492

On your mentor (Main) character -

1) Click on the community button (Top right corner 2nd in)

2) Select Friends List

3) Select/High-light the Apprentice characters name

4) End apprentice button should no longer be greyed out (in active)

5) Click End Apprenticeship button. - Done

stoneship

Thank you.