It’s probably too late...but make sure you are entering your name correctly ...surname/first names <exactly as they appear on the ticket>. Do not use the 6 digit alphanumeric booking code that you would normally use on a US airline. Use the 13 digit ticket number. If you booked on the Delta website, you probably won’t be able to book a seat. But actually I don’t think any of this will help you, because the flight will be under airport control by now (24-48 hours) so you’re probably going to be locked out. Oh...don’t try to check in online...you will just get disappointed and stressed!! Good luck! Try to remember it’s primarily an Asian carrier, doing a little bit of international, not a western-style airline based in Asian running international only (CX, SA, KE etc)...they do things differently on board. For example, when you get on board you probably be asked to order both meals and you won’t keep the menu; Chinese have no real understanding of people who have ice in their drinks, or even cold drinks (this will be a culture shock if you’re from the US, where ice makes up 60% of the drink!!). Only about half the staff will speak English, but if you can’t make yourself understood, they’re usually pretty good at getting an English speaker for you. Finally, can I just warn you that the airline is owned by the government of the PRC...follow the rules, they’re not optional extras. Finally, they close lavatories about 45-30 minutes out from landing...and they are ACTUALLY closed...,so be prepared. I’ve flown them a lot in the last 3 years and they’re great...just different. Other than Chins Eastern, they can’t be beaten on price.