I’m trying to get at the 20/2/2017 to travel from Xian to Shanghai by bus.

Two schedules are available from Fangzhicheng Bus Station to Shanghai at 13:00 and 15:00, and only one bus leaves from Sanfuwan Bus Station at 16:00.

You are suggested to book immediately. Search for the website by inputting "xaglkp", but it only has Chinese version. Turn to your Chinese friend. Or dial 96716 to ask whether they sell ticket on phone.

Good luck!