Bought Shinkansen ticket without adding oversized luggage, and now I want to add one.

Hey everyone,

I bought a Shinkansen ticket from Tokyo to Kyoto through Klook and got my ticket via the machine, but I forgot to add luggage. Now I need to figure out how to add it.

Can I change the ticket type/add the oversized luggage at any station or does it have to be the one I am departing from?

Thanks!

by Nalotaib