Quick Replies Needed: Can you change train tickets?

So just to confirm what the other have said above, you can change and refund tickets, but you usually have to find the correct counter in whatever station your are in. Changing tickets is free, and refund you get most of your money back.

Thanks for the help, made my trip to Shanghai a lot easier!

...lots of people go on trains without a ticket, or rather with a ticket for a later or earlier train. That's almost a whole other topic...I travel by train a lot, and the whole topic is still largely a mystery to me.

Same here, I'd love to be able to understand the intricacies of the system.

Disclaimer - I hate playing the dumb laowai card, most of my bad train habits I actually learned from Chinese friends.

After buying a ticket, I've jumped on earlier trains that had "no tickets" available at the ticket office - only to find whole carriages empty once I am actually on the train. 

Sometimes it's totally OK to 补票 （bǔpiào） (buy or upgrade your ticket on the train) and they'll even wave you on to the train at the gate if you ask, other-times it's a flat 'bu keyi' and the stink eye.

Once I didn't have the right ticket and the conductor I spoke to apparently couldn't be bothered dealing with me 'cos she just sent me to the far end of a very long train to upgrade and when I got there there was no one on duty...It was only a 20 minute ride, so...

Lots of times those empty berths or seats are because people have bought tickets gettin on at later stations. I've been unable to upgrade from a seat to a sleeper with sleepers visibly empty and it is really frustrating but there's nothing the train staff can really do about it.

I really wouldn't recommend getting on a train without a ticket unless you're ok with staning room only and even then, if it is a crowded train I wouldn't risk it.

Lots of stations will check your ticket when you leave the station after arriving. If you don't have a ticket they'll make you pay for one, even if you've simply lost your ticket stub.

The Chinese train system is easily the best managed public utility in the world. And the only thing they can manage to do better than anyone else in the world. WORD.

Trains depart and arrive thousands of kms later almost to the minute. You can easily switch tickets at a loss of only 5% of the ticket cost. You can usually cram on almost any train albeit without a reserved seat.

BTW, a little known trick...if you are stuck on a train with no assigned seat, just go to the middle of train (the dining car) and hang out there at a table for the length of the ride. Sure, you'll have to buy a bottle of beer or a noodle dish every hour or so to be able to stay,  (or pass out cigarettes to the staff that hangs there during dead times), but it beats standing and cramming into the space between cars with the returning students and their luggage.

...if you are stuck on a train with no assigned seat, just go to the middle of train (the dining car) and hang out there at a table for the length of the ride. Sure, you'll have to buy a bottle of beer or a noodle dish every hour or so to be able to stay...

A friend and I did this and we drank the buffet car out of beer.  It was only a 4.5 hour journey...