The log is the price
Every change to every record carries who, when, from which login, which address and which machine — and the log is read on one page, by support and by the hotel.
The product lets people do a great deal — the administrator can correct an audited booking, the desk can waive a balance, a supervisor can override an over-occupancy. Each of those is allowed because each is written down.
What is written
The login, the role, the IP address and the machine, the time, what changed from what to what, and the reason where one was asked for. On the record's own timeline and on the operations log.
What cannot be done
The log is append-only. Nothing in the application can edit or delete a row of it, and the database role the application runs as has no grant to.
Who reads it
The hotel, on the operations log. Support, when asked what happened. The auditor, who asks for it last and gets it first.