If lcase(Range("f17").Value) = lcase("Yes") Then 'For 1st Sunday
   Range("f18,p17:p18,j17:j18").clearcontents
elseif ....

wichie,

If you want to toggle the yes-values in the six cells, you could use this
code, placed in the VBA-module belonging to the worksheet:

Private Sub Worksheet_Change(ByVal Target As Range)
   Dim rng As Range
   Dim rngD As Range
   Dim rngTemp As Range
   Set rngD = Me.Range("F17:F18,J17:J18,P17:P18")
   If Target.Count = 1 And Not Intersect(Target, rngD) Is Nothing Then
       If LCase(Target) = "yes" Then
           For Each rng In rngD
               If rng.Address <> Target.Address Then
                   If rngTemp Is Nothing Then
                       Set rngTemp = rng
                   Else
                       Set rngTemp = Union(rngTemp, rng)
                   End If
               End If
           Next
           rngTemp = Null
       End If
   End If
End Sub

Otherwise the next code might the shorter one you asked for:

Sub ToggleYes()
   Dim rng As Range, rngL As Range, rngD As Range, rngTemp As Range
   Set rngD = Me.Range("F17:F18,P17:P18,J17:J18")
   For Each rng In rngD
       If LCase(rng) = "yes" Then
           For Each rngL In rngD
               If rngL.Address <> rng.Address Then
                   If rngTemp Is Nothing Then
                       Set rngTemp = rngL
                   Else
                       Set rngTemp = Union(rngTemp, rngL)
                   End If
               End If
           Next
           rngTemp = Null
           Exit For
       End If
   Next
End Sub

Jan