disenroll       
verb [ I or T ] US uk/ˌdɪs.ɪnˈrəʊl/ us/ˌdɪs.ɪnˈroʊl/
 退出,取消注册;除名
to remove someone's name or your own name from a list, for example a list of members of an organization or of a medical care plan
  Some preschool providers are willing to work with parents of children who hit or bite, but others quickly "disenroll" (in other words expel) the child. 一些幼儿园愿意与打人或咬人的孩子的父母合作,但其他幼儿园则迅速将孩子“注销”(换句话说,就是将他们开除了。) 
 You may enroll/ disenroll /change at any time during the year. 您可以在一年中的任何时间注册/退出/更改。 
 - More examples
 - If the proposal to change the eligibility for health and dental care passes, we will have to disenroll a lot of children.
 - The Cherokee Nation in Oklahoma voted this year to disenroll about 2,800 members.
 - They fear the new council will ultimately disenroll them.
 - Anyone who wishes to leave public school later on will be subject to conditions they will have to meet in order to disenroll.
 - Options should include the ability to disenroll or switch vendors at any time.