Problem
Users
On the current payment page, people could'nt verify all their details and often contacted support due to filling errors - changes to airfare after purchase are chargeable.
Business
Conversion to payment dropped from 5% to 2% - the reason was unknown
Process
Assumed that if the price and the target action are in focus, the conversion rate will increase.
Decided that we should add viewing of all data right at the payment stage - it is technically impossible to change it, but this way we will take care of passengers a bit.
Hid payment methods to keep the last used one and leave the possibility to see all possible ones in one place.

Link to payment page prototype
Testing and feedback
The product manager had a hypothesis that people wouldn't see how to change the payment method and suggested adding an "Edit" button - I thought otherwise.
To find out the truth we went out to test solutions with our clients.

I used unmoderated usability testing on the Useberry service, with SUM measurement.

In the end, the variant with the "Change" button won out, and we settled on it. Because, after all, we make the interface for our clients, not for ourselves.
Results
Each solution we have rolled out for prolongation only through A/B tests, here the situation has not changed.
The first thing that made me happy during the test was that the conversion did not break, but increased by 1% for the last stage of the funnel this is just a holiday.

The problem of users has also been solved - the number of requests to support for passport data changes has decreased by 2 times.