Hello,
I have a return flight from Munich to Athens this June. I had to re book my return time from 6 am on the 7th of June to 7pm as I would not be able to be at the airport a 6am. I have never flown before this will be my first time. Just wondering what I need to take with me to check in for the flight?
Do I need to print out my email including the rebooking fee one or do I just need the reservation code?
Also it says something about having the credit card you paid with on you incase they need to look at it, I would have though the passport would be enough.
Thanks,
Amy

Passport is all you need.

If you use a check-in kiosk then you need your booking confirmation code, your last name, and passport. The credit card is used to identify you at a kiosk but a passport works just as well..

You can check in online 24 hours before your flight to make sure everything is correct. Print your baording pass and all you need to do is go to the luggage drop off with your boarding pass and passport and get your baggage tags.

In case you cannot print your boarding pass and cannot use mobile phone check-in:
For an intra-Schengen flight, all you need at the check-in kiosk is your booking confirmation number.
The kiosks are located on the level you enter Terminal 2 if you go to the airport by S-Bahn/rail.
You can also try to identify yourself at the kiosk with your credit card, but if that should not work the six-digit confirmation number will work.
After the kiosk printed your boarding pass you go one level up to bag drop.
Either manned bag drop desks or self-service bag drop counters left and right at the edge of the terminal.
You don't need your passport to go through security and later to board your flight. (But you should have it with you). All the security and gate agents want to see is your boarding pass.

Thank you Most helpful everyone, especially @Cowboy1968