Objects (e.g. seats or booths) on a seats.io chart have two kinds of labels:
a "technical" label
a "displayed" label
When you book an objects, we use the technical label of that object to store the booking. If you change the technical label of a booked object through our designer, that object will appear to be free again.
E.g. let's say the seat with technical label "B-24" has been booked. If you rename row "B" to "C", the seat becomes selectable again for ticket buyers. Same thing if you change the seat number "24" to "48".
Afterwards, if you revert to the original technical label, the object will appear booked again.
Changing the displayed label does not influence bookings. Ticket buyers will just see a different label displayed in tooltips.
You should always use the displayed label when showing an object name in your website, e.g. in the overview of which places the ticket buyer has selected. Same thing for the tickets you issue: those should contain the displayed label and not the technical label.