The wife in a family law matter applied to vary a divorce Judgment and compel the Respondent husband to pay retroactive child support. Justice Yungwirth commented that, under Rule 12.41, the preferred approach is to file and serve a Notice to Disclose in form FL-17, before an Application to vary child support is filed. Rule 12.41(6) requires the Applicant to serve the Notice to Disclose, and any documents required to be disclosed to the other party, pursuant to subsection 21(1) or 25(4) of the Federal Child Support Guidelines, or 21(1) or 22(4) of the Alberta Child Support Guidelines, not later than one month before the Application is scheduled to be heard or considered as set out in the Notice to Disclose. Yungwirth J. held that the Respondent’s conduct was blameworthy in relation to his child support obligations, and made an award for retroactive child support.