Agentic Commerce and the rail booking process

The typical online rail booking process (roughly) breaks down into several well known steps:

1. Origin & Destination search, with additional date & time and Railcard / concession parameters to find a journey

2. Selection of a single fare, usually the cheapest, from a range selected - maybe done twice for a return

3. Addition of extras, such as seat reservations 

4. Payment and confirmation 

Currently a lot of AI Agent work I have seen focuses on the first step and maybe the second (if the rule is to always find the cheapest single). 

But the real purpose of Agentic Commerce is to complete all 4 steps automatically on behalf of a customer. Ideally without any human intervention.