What is the effect of a written settlement agreement setting custody and access?

This application raises a number of issues. The first is the effect that a written settlement agreement setting custody and access has on a subsequent application by one of the parties to vary custody or access. Essentially the issue is whether the test set out in Miglin v. Miglin, [2003] 1 S.C.R. 303, 2003 SCC 24, 224 D.L.R. (4th) 193 for the variation of support agreements has any application to custody agreements. Related to this issue is whether the legal effect of the agreement can be undermined by one of the parties arguing that it was signed under duress. Another issue is the ability of a parent with joint custody, by agreement but not by order, to relocate the children. Changes to Custody Arrangements