Sub HoursMinutesBetween(Startime As String, Endtime As String) As String
Dim diff1 As Period
DateTime.DateFormat= "MM/dd/yyyy hh:mm a" 'you must involve the date also. You can use a different date format
diff1 = DateUtils.PeriodBetween(DateTime.DateParse(Startime), DateTime.DateParse(Endtime) )
Return $"${NumberFormat(diff1.Hours,2,0)}:${NumberFormat(diff1.minutes,2,0)}"$
End Sub