WhatsApp booking from the gate
Booking on WhatsApp means arranging and confirming a session in writing, in one message thread that becomes the record of the hour, the length and the fee.
Phone calls do not survive transit well. Gate announcements drown them, roaming charges punish them, and the passenger in the next seat hears every word. The house therefore books by message. WhatsApp carries most threads, Telegram is available as well, and the booking line for both is on the booking page. Lounge or in-flight Wi-Fi is enough; nothing needs a local SIM.
A first message written between flights
A first message can be answered without a round of questions when four things are present: the hotel area or terminal, the date and start time in Amsterdam time, the length from the ladder, and whether a particular therapist is wanted. Give the local hour rather than the one on your wrist, since a phone that has not yet changed zones is the commonest cause of a booking set for the wrong hour; the time zone entry covers that trap. The room number can follow once you have a key.
What comes back
The reply says whether the therapist you named is free at that hour, or lists who is, and the choice stays with you. It gives the price for the length you asked for and, where a deposit applies, the amount. Payment details appear in that same thread, and only there, once the hour is agreed; nothing about payment comes before that point. A message from another number claiming to act for the house should not be paid.
The thread as a boarding pass
Once confirmed, the thread is the record of what was agreed: start, length, fee, the half sent ahead and the half due at the door. On a tired arrival it is easier to scroll back to than to remember. It is also where you hear if the hour has to move, and where you say so if your flight does. Keep notifications on for that conversation until she has arrived; if your battery is failing, the journal note on booking with a dying phone is worth two minutes of the charge that remains.