Нет такой функции потому что не присоеденина библиотека Visual Basic For Applications

Ну значит Microsoft Visual Basic for Application
вообще я в ранних версиях написал сам её

'Public Function Replace(stringS As String, stringToReplace As String, replacementString As String, Optional start As Long = 1, Optional count As Long = 0, Optional compare As Integer = -1)
' Dim temp As String
' Dim intPos As Integer
' Dim intNachPos As Integer
' Dim intCOUNT As Integer
' intNachPos = start
'
' temp = stringS
' intCOUNT = count
' If intCOUNT = 0 Then intCOUNT = Len(stringS)
' Do
' intPos = InStr(intNachPos, temp, stringToReplace)
' If intPos > 0 And intCOUNT > 0 Then
' 'Debug.Print Mid(temp, intPos)
' temp = Left(temp, intPos - 1) & replacementString & Mid(temp, intPos + Len(stringToReplace))
' 'Mid(temp, intPos, Len(stringToReplace)) = "q" ' replacementString
'
' 'Debug.Print Mid(temp, intPos)
' intCOUNT = intCOUNT - 1
' End If
' intNachPos = intPos + 1
' Loop While intPos <> 0
' Replace = temp
' 'Debug.Print stringS
' 'Debug.Print temp
'End Function