Sub AdvanceTimes_v2()

    Dim tmp, cel As Range
    Dim firstTime As String
    Dim secondTime As String
    
With Sheets("Sheet1")
    For Each cel In .Range("B3:C25")
        If InStr(Trim(cel.Value), ":") = 3 Then
            tmp = Split(cel.Value, "-")
            firstTime = CStr(Format(DateAdd("h", 1, CDate(tmp(0))), "hh:mm"))
            secondTime = CStr(Format(DateAdd("h", 1, CDate(tmp(1))), "hh:mm"))
            cel.Value = firstTime & "-" & secondTime
        End If
    Next cel
End With
End Sub