Convert DateTime to Local with TimeZone using C# and VB.Net in ASP.Net

Dear All,

I have done an application which runs on C# and Asp.net. The application does hotel room booking send cancelation details. But I am having an issue in UTC time. Example: Hotel in Sri Lanka and client in the USA. But application runs on Singapore server. These three countries time difference I am unable to send email exact date. email sending server in UTC time +8:00 and Hotel in UTC +5:30 and client in UTC -6:00.