Oh, we can do better than that:

Dear Management:

Mister Offer will be unable to conduct his scheduled class on Monday; he has answered a higher calling to attend to the needs of his flock, an international conclave of aspiring souls who rely on his spiritual guidance to save their souls and indeed, in this hour of need, their very lives.

We regret any inconvenience this may cause, but we felt you would understand that where mortal peril is concerned, scheduling convenience must give way in favor of immediate intercession.

We will take every care to ensure Father Offer is returned to you unharmed to resume his normal teaching duties (although no guarantees can be offered, due to circumstances which may well be beyond our control).

Thank you for your understanding.

Board of Directors
Father Offer Society