This question refers to the text "An Apprenticeship Agreement from 1250" from the lesson The Rise of Europe.
In this text, we are able to see an agreement that was drafted between Ouede Ferconne and Matthew Haimart. In this agreement, Ferconne states that she agrees that her son Michael will become the apprentice of Haimart for four years in order to become a weaver. However, after two years, Ferconne will be able to legally purchase her son back.
There are several reasons why Ferconne might want to buy Michael back. Michael might not like the profession, and he might wish to change it. Moreover, Michael might be unhappy with Haimart. Michael might also believe that he has learned enough after two years, and that four are unnecessary. All of these reasons could lead Ferconne to purchase Michael back.