Update the quantity of lines already in a cart
Changes the quantity of one or more lines already in the cart, identified by their line id, and returns the updated cart with recalculated totals. For a timed ticket or package, increasing the quantity re-checks availability for the date and time already on the line, so the call can fail if the held slot no longer has enough capacity.
Headers
Identifies which store this request is for. Required on every store-scoped route. It is not authentication and not a secret — it grants no privileges and is safe to send from a browser. You receive the value once your Entria backend has been created and configured. Missing header returns 400; an unknown store returns 404.
Request
One or more line updates. Each entry changes the quantity of a single existing line; a lineId may appear at most once (400 otherwise).
