Absolute to Relative Referencing

Hi All,

I have the following code which inserts a sum formula in the activecell.

Dim startRow As Integer
Dim startCell As Range, endCell As Range
startRow = 2
With ActiveCell
Set startCell = Cells(startRow, .Column - 1)
Set endCell = .Offset(0, -12)
.Formula = "=SUM( " & startCell.Address & ":" & endCell.Address & ")"

My problem is that the sum formula is created with absolute references.
I need the formula to be created with relative references for both the rows
and the columns.

Any ideas on how to change from absolute to relative referencing?

Thanks,

Steve