Guests ask some version of this question every week. Does the hotel know? Is there an understanding with reception? Should I mention it when I check in? Is there someone downstairs who handles this?
The house has no arrangement with any hotel and asks for none. That is a plain fact about how bookings work here, and the reasons are worth explaining, along with what it means for the guest.
A visit, not an arrangement
A booking here is a guest receiving a visitor in his own room. Hotels deal with that every evening and set their own rules for it. Some ask visitors after a certain hour to give a name at reception, some ask that visitors be collected from the lobby, and some ask nothing at all. None of that needs an understanding between the hotel and anybody else. It needs the visitor to follow the rule, and she does.
Why an arrangement would not help
Hotels change managers, owners and policies constantly, and a private understanding with one duty manager would last only as long as he did. A visit that follows the building's own rules works the same way in a canal-house hotel of twenty rooms and a tower of four hundred, whoever happens to be on duty that night.
What a night desk actually does
A night porter registers late arrivals, answers the switchboard, takes a delivery, deals with a key that has stopped working on the sixth floor, and helps the guest who cannot make the television turn off. Receiving visitors to guest rooms is part of that ordinary work, and a visitor who is asked where she is going answers as anyone would.
What the guest can do
If you do not know what your hotel expects of visitors, ask reception. It is a routine question, and the answer is useful: whether a visitor should be announced, whether you should come down, whether the lifts need your card after a certain hour. Put the answer in your booking message and the arrival is planned around it.
Nothing beyond that needs explaining to anyone. Why a guest has a visitor is his own business, in a hotel as anywhere else.
On the house's side, the rest is practical: a small bag, linens that leave with her, and an arrival timed to the rules the guest has passed on. The other questions guests ask before a first booking are answered on the FAQ, and the arrival itself is described step by step on the hotel massage page.