Delays are not an edge case in this line of work. They are the weather. A booking arranged from a departure lounge somewhere else in the world is a booking made against a landing time that has not happened yet, and landing times move. Nobody here is surprised by it, and nobody treats it as a problem you created.
The money deserves a plain statement, because it is the source of most of the anxiety. Half the fee goes ahead on nearly every booking and always on an airport one, and the balance is paid on arrival, by card, in crypto, or in cash, euro or another major currency, with the exact amount in that currency confirmed in writing before she sets out. A booking can move to another date once without losing that half, provided the request comes more than 24 hours before the start and the new date is within 14 days. A delay that surfaces on the day sits inside those 24 hours, so moving the booking then counts as a cancellation, and what helps is telling the office early enough that the booked hour can still be kept.
Book a window, not a point
The single most useful habit is to stop sending an exact time and start sending a shape. Instead of ten o’clock, send the landing time, whether you have baggage in the hold, and where you are sleeping. From those three things the arrival can be worked out on this end, and more importantly it can be re-worked when the first of them moves.
An arrival window in the centre is forty to sixty minutes, uniform, and that figure does not change with the hour. What changes is everything upstream of it: immigration, a belt that takes forty minutes, a train or a car, a front desk, a room that is not quite ready. Build the message around the flight rather than around the clock, and the booked hour has margin in it before any delay arrives.
Send the new number, not an apology
When the delay appears, send the revised landing time. That is the whole message. No explanation is needed, and the reply says plainly whether the booked hour still stands. The roster runs to 45 therapists and it runs around the clock, which is the actual mechanism behind the flexibility. It is not goodwill. It is simply that at two in the morning there are people working.
Send it as soon as you know, even from the air if you have signal, and even if the new time is uncertain. Half-information early beats exact information late. A delay reported three hours out leaves room to keep the hour. A delay reported as you are collecting your bag usually leaves none.
The one thing a delay can genuinely change
Not the price, not the availability, not the technique. The therapist. If a specific person was arranged for ten in the evening and the flight now lands at half past midnight, the two and a half hours in between belong to someone else’s evening. Sometimes the booked hour survives the delay and sometimes it does not, and you will be told which it is rather than discovering it at the door.
This is the one argument for naming a flexible preference rather than a single name when you are booking around an inbound. If you have read the roster and there are two or three you would be glad to meet, say so at the start. It adds nothing to the fee and it removes the only real casualty of a delay.
When the delay changes where you are sleeping
Occasionally a delay does not just move the hour but moves the address. A missed connection turns a night in the centre into a night by the runway. That is a different arrangement rather than the same one shifted: central Amsterdam runs on the standing forty to sixty minute window, while Schiphol hotel rooms are arranged on enquiry. Both are possible at any hour. They are simply organised differently, and the airport guide explains what the second one involves.
The summary is short. Send the flight, not the hour. Update it the moment it moves. Name more than one preference if you have one. Remember that a date move needs more than 24 hours of notice, and the clock is not the enemy it feels like at the gate.