Changing the name of a Defined List in Name Manager using VBA?

So I have:

Sub DefineCableType()

    ActiveWorkbook.Names.Add Name:="Size_" & "CELL NAME", RefersToR1C1:="=offset(R2C" & ActiveCell.Column & ",0,0,COUNTA(R2C" & ActiveCell.Column & ":R90C" & ActiveCell.Column & ")-COUNTBLANK(R2C" & ActiveCell.Column & ":R90C" & ActiveCell.Column & ")+1,1)"
    
End Sub

What I want is that when the active cell is selected (ex. Assuming cell O1 is the active cell and its contents are COOKIES), the contents of that cell are named to CELL NAME. This means that the name of my list will now be Size_COOKIES.

..I can't seem to figure this one out. Please help.