Can I see which of my staff changed a booking and when, if a customer says they were told something different?

Yes, in most travel back office systems every booking carries its own history, so you can open the file and see who created it, who changed it and at what time. That usually covers things like a change of travel date, a new passenger name, a markup being edited, a cancellation being started or a payment being marked as received. For a disagreement with a customer, this is normally enough to tell you what your office actually did and when.

The honest limit is that the system can only record what happened inside the system. If one of your staff promised something on the phone, over WhatsApp or in a personal email, that will not appear anywhere unless they saved a note against the booking. This is why most agencies make it a rule that every conversation with a customer gets a short note in the booking file. Once that habit is in place, the history becomes a real account of the file rather than just a list of clicks.

How far back the history goes, and who is allowed to look at it, depends on your plan and on how your user roles are set up. In many setups only an owner or a manager can view the full trail, which is sensible, because staff should not be able to quietly check or clear their own record. Some suppliers also send their own change messages, and those sit alongside your staff activity so you can tell an airline change apart from something your office did.

If this matters to you, open one of your recent bookings, look at what the history already shows you, and then ask for note taking on calls to be made compulsory for your team.