On your What:="-G"
you need to add "space
-G
space"
Assuming that's what your trying to do
Example here
Option Explicit
Public Sub Example()
With ThisWorkbook.Sheets("Part_Number").Range("F:F")
.Replace " -G ", " ", xlPart
End With
End Sub
Example
WA-2001 -G WA-GSK024
To this
WA-2001 WA-GSK024
Edit Use this if there is no space
Option Explicit
Public Sub Example()
Dim rng As Range
With ThisWorkbook.Sheets("Part_Number")
For Each rng In .Range("F1", Range("F99").End(xlUp))
If Right(rng.Value, 2) = "-G" Then
Debug.Print rng.Value ' Immediate Window
rng.Value = Mid(rng.Value, 1, Len(rng.Value) - 2)
Debug.Print rng.Value ' Immediate Window
End If
Next
End With
End Sub