They should reach out the same way that you would during normal business hours. We have a primary and backup support engineer on call every single night, including holidays, weekends, etc.
We won’t nickel and dime you for service requests that are on the fringes of business hours. However, if a ticket should require immediate assistance and is clearly after hours, we will confirm with your authorized contacts before proceeding. This is to avoid an unexpected bill at our after hour’s rate.