I dug this up from a loong time ago so please excuse the coding but it
does work and probably doees what you want. As you can
see I type the range into the code.

The two important bits are locF = cel.Formula and cel.Formula = locF.

You could also do a Ctrl H and just search  & replace if it's a simple.

Sub subChangeCells()
' Massage formulas  in a hard coded range.

Dim locF As String
Dim locFStart As String
Dim locFEnd As String
Dim cel As Range
Dim locN As Integer
Dim locN1 As Integer
Dim locChr As Integer
Dim locFRange As String
Dim locChr2 As Integer
Dim locLen As Integer

locN = 1
locChr = 1
locFEnd = ","""")"
For Each cel In Range("a8:an8")

locF = cel.Formula
locChr = InStr(locF, "!")
locF = Mid$(locF, 1, locChr) & "$" & Mid$(locF, locChr + 1, 1) &
"$" & Mid$(locF, locChr + 2)

cel.Formula = locF
Next cel

MsgBox "Change cells Done"
'