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To remove an existing eticket file simply send an empty value {"eticket":""}. Removing an eticket file will also remove the barcode as well. PUTting a new eticket file will overwrite an existing one as well as remove/overwrite the existing barcode.
To remove an existing barcode simply send an empty value {"barcode":""}.
You cannot add multiple etickets or barcodes in a single API call, you must make a separate PUT for every seat.
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