You can’t book a 7-seater Uber in New Zealand. There is no such option on the Uber app for requesting Uber based on the number of seats. You should book multiple Uber cars based on the information you provided above to travel from the Airport to Sumner.
You might be looking for Uber with more than 5 Seats or otherwise called Uber XL. Unfortunately, in NZ we don’t have such a service for Uber or any other rideshare platforms. This is due to some Transport authority rules I think.
