If cell equals "CR" then make cell to left negative and delete "CR".......

You said the cell to the left, but Offset(0,1) is the cell to the right. Offset(0,-1) would be the cell to the left. Not sure which you want, adjust the code below accordingly.

Sub pas()
With Range("A:BA")
Set c = .Find("CR", lookat:=xlWhole)
If Not c Is Nothing Then
FirstAdd = c.Address
Do
c.Offset(0, 1).Value = c.Offset(0, 1).Value * -1
c.ClearContents
Set c = .FindNext(c)
Loop While Not c Is Nothing And c.Address <> FirstAdd
End If
End With
End Sub