Be to

 "Be to" is a phrase that indicates an expected action or event in the future. For instance, "I am to meet my friend at the park tomorrow" means that I have a plan to meet my friend at the park. It can also express a scheduled arrangement, like "The flight is to depart at 9 a.m." which means the flight is scheduled to leave at that specific time. In both cases, the phrase highlights a planned or anticipated occurrence.