Board policy 4150 A.1.b addresses legacy students (grandfathering). The relevant text from the policy is below.

As a consideration to balance stability in developing student attendance lines, student assignment plans will include the following limited options:

• To the extent practicable, a student who is reassigned will be provided an opportunity to stay at the current school for one additional year if it is the terminal grade for an elementary or middle school (grades 5 and 8), and the student’s siblings will be provided an opportunity to attend the same school for the one year period (and for an additional year if the year is the terminal grade).
• To the extent practicable, any student currently in high school who is reassigned from an existing school to an existing school will be provided an opportunity to stay at the current school until the terminal grade (grade 12).
• Additional opportunities to remain at the current school, including for siblings, may be included in the student enrollment plan.
• A change in domicile (move to a new address) does not preserve the previous school assignment.