I am trying to make a macro find and replace one week with another. I have the two cells to reference the two weeks and I created a macro but it doesn't work. It just highlights the cells I need replaced and that is all. Not sure what I am doing wrong.

Sub FindReplace()
'
' FindReplace Macro
'

'
WeekNum1 = Cells(5, 15) 'previous week location
WeekNum = Cells(4, 15) 'location of week

Columns("A:L").Select
Cells.Replace What:="Week " & WeekNum1 & " ", Replacement:="Week " & WeekNum & " " , LookAt:=xlPart, SearchOrder _
:=xlByRows, MatchCase:=False, SearchFormat:=False, ReplaceFormat:=False

End Sub