How to send email at a specified time?

I have a process at the end of which, an email needs to been sent to several people as a reminder for an upcoming event.

The email won't be sent till a certain days, say 2 days, before the event date.

How can I control this in the K2 Studio? Should I use a timer or a loop to keep the K2 checking the time and when the it reaches the right time, send the email.

The following is the K2 code for a server mail event. I suppose we should do the looping in this section of code:

public void Main(ServerEventContext K2)
{
SMTPFunction(K2);
}
public void SMTPFunction(ServerEventContext K2)
{
System.Web.Mail.MailMessage objMsg = new System.Web.Mail.MailMessage();
System.Web.Mail.MailAttachment objAttachment;
object strFrom = "";
object strEmail = "";
object strSubject = "";
object strBody = "";
object strMailServer = "";
strMailServer = K2.StringTable["SMTP Server"];
System.Web.Mail.SmtpMail.SmtpServer = strMailServer.ToString();
strFrom = K2.ProcessInstance.Originator.Email;
strEmail = "abc@abc.com"! ;
if((strEmail==null)||(strEmail.ToString().Trim().Length == 0))
{
throw new System.Exception("No Email Address was supplied, please rectify and try again.");
}
strSubject = "Notification";
strBody = "There is an event on:" + System.Environment.NewLine + "" + System.Environment.NewLine + "Thanks," + System.Environment.NewLine + "" + K2.ProcessInstance.Originator.Name + "" + System.Environment.NewLine + "" + K2.ProcessInstance.Originator.Email;
objMsg.From = strFrom.ToString();
objMsg.Subject = strSubject.ToString();
objMsg.Body = strBody.ToString();
objMsg.To = strEmail.ToString();
objMsg.Subject = strSubject.ToString();
objMsg.Body = strBody.ToString();
System.Web.Mail.SmtpMail.Send(objMsg);
}