Key-card lifts, and meeting her downstairs
A key-card lift will not climb to guest floors until a room card is tapped, so a visitor cannot ride up alone. The answer is to meet her at the lift lobby.
Many airport hotels have lifts that only move to guest floors when a room key card is held against a reader inside the car. Without a card, the lift will go only to the ground floor, or to public floors such as a restaurant or a gym. Some hotels lock every floor all the time; others lock only the executive levels, or lock all floors after ten or eleven at night.
How to find out
Test it on the way up after checking in. Step into the lift and press your floor without tapping the card. If the lift moves, the lifts are open. If nothing happens, they are not. The front desk can also tell you, including whether the rule changes later in the evening.
The arrangement
If the lifts are locked, the guest meets the therapist downstairs. The time is agreed in the thread; the guest is told when she is close; the guest takes the lift down, meets her by the lifts or at the entrance, and rides back up with her. It takes a few minutes.
Mention it in the thread
Say in the booking thread that the lifts need a card, ideally when you share the room number. That way nobody arrives expecting to come straight up, and nobody stands in the lobby with no way to reach your floor.
Things that do not work
Leaving a key card at reception for a visitor does not work; reception will not hand it over. Asking staff to accompany a visitor up puts them in an awkward position. Going down half an hour early to wait is unnecessary. Wait in the room until you hear she is close.
Leaving
Lifts nearly always travel down without a card, so she can leave on her own. The journal note on meeting her at the key-card lift goes into more detail.