Is this what you mean (I have changed the code to make it simpler to change the text)
Private Sub Worksheet_Change(ByVal Target As Range)
Const msg As String = "You have chosen - "
Const msg_Guaranteed As String = "your total ammount of hours are not to exceed the guranteed hour"
Const msg1 As String = "When working Offshore you are only entitled, to book 12,00 hours a day in total"
Const msg2 As String = "When working Offshore you are only entitled, to book 8,00 hours per travel in total"
Const msg3 As String = "Please consider, to give detailed description and with an NCR number if applicable"
Const msg4 As String = "When Indirect time, check your garanteed hours for this day, " & msg_Guaranteed
Const msg5 As String = "When Indirect time, check your garanteed hours for this day, " & msg_Guaranteed
Const msg6 As String = "When Indirect time, check your garanteed hours for this day, " & msg_Guaranteed
Const msg7 As String = "When Indirect time, check your garanteed hours while at Home, " & msg_Guaranteed
Const msg8 As String = "Offshore Transport hours, are not to exceed 12,00 hours per day"
If Intersect(Target, Range("F1:F123")) Is Nothing Then Exit Sub
If Me.Cells(Target.Row, "S").Value > 8 Then
Select Case Target.Value
Case "Transport Hotel/Site - Site/Hotel": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg1, vbExclamation
Case "Travelling Onshore (home/site - site/home - site/site)": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg2, vbExclamation
Case "Work time Onshore": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg3, vbExclamation
Case "Indirect time on site Offshore": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg4, vbExclamation
Case "Indirect time on site Onshore": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg5, vbExclamation
Case "Indirect time off site Onshore (abroad)": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg6, vbExclamation
Case "Indirect time off site Onshore (home)": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg7, vbExclamation
Case "Transport Offshore": MsgBox msg & vbNewLine & Target.Value & vbNewLine & vbNewLine & msg8, vbExclamation
End Select
End If
End Sub