Calculate First Sunday of the Month

Calculate First Sunday of the Month

Our TimeSheets run Sunday through Saturday.  Certain compensation changes have an effective date of the first Sunday in the month following the approved changes.

I'm struggling with calculating the first Sunday of the month following the change.

What I'm working with right now which is not working:

monthstart = toStartOfMonth(input.Date_Change_Requested);
firstmonth = monthstart.addMonth(1);
firstsunday = firstmonth.getDayOfWeek(0);
input.Effective_Date_of_Change = firstsunday;

Thank you!

Jesse