If I miss a train on which I have a reserved seat, can I take another train instead? If not, can I get a refund? Does this involve a handling fee?

Reserved Limited Express tickets become invalid once the departure time of the specified train has passed, and changes or refunds are not possible. However, if you miss your train, you can
use your ticket for a non-reserved seat on a train for the same zone on the same day. If you have not used the basic fare ticket, you can receive a refund after paying the handling fee so long as the expiration date has not been exceeded.