What is the test for a variation of a support order?

In McCullough v. McCullough, [2003] P.E.I.J. No. 66, DesRoches C.J. summarized “material change in circumstances” at paragraph 10 as follows: In the basic law of variation, the original order is presumed correct. The court may only vary the previous order if there is a material change in circumstances. The burden of identifying such change is on the party seeking variation. Changed circumstances alone will not warrant a variation of the existing support order. If there is no material change, the motion is to be dismissed. "Material" is defined as substantial, unforeseen, and continuing in nature. (See Mullin v. Mullin, [1993] P.E.I.J. No. 69).