You should be the owner of your Pass

Only the owner of the Eurail Pass can use it:

• Eurail Passes are issued on identity and cannot to be used by any other person.
• Your name, country of residence and Passport number should be filled in on the Pass.

Travel days need to be filled in correctly

• The Eurail Global Pass (10 days in 2 months and 15 days in 2 months), Eurail Select Pass, Eurail Regional Pass and Eurail One Country Pass have a schedule with boxes where you should fill in the date of travel for each day on which you travel.
• You should always fill in the date of day of travel before boarding the train. One day of travel is from 0 am to 12 pm.
• If you make your first trip of a travel day on an overnight trip on a DIRECT night train leaving after 7 PM, you will only need to fill in the date of the following day
• There are free bonuses and reduction bonuses that entitle you to reductions. If you use a free bonus on a certain day, you will have to fill in a travel day on your Pass. This does not apply when you use a reduction bonus only. You can use the reduction bonus anytime within the validity period of your Pass.
  

Traveling in a group

When traveling on a Saver Pass (the Eurail Pass that offers a 15% discount to groups of travelers; Eurail Global Pass, Eurail Select Pass, Eurail Regional Pass and Eurail One Country  Pass) you should travel together as the names of all the persons that travel together will be on just one Pass (max. 5 names). This means that if one or more persons decide to stay at home for a day and the others go traveling they will, the home-stayers will have one travelday less. As those who do travel should always be able to present the Pass to the train staff. Therefore, two groups cannot make separate journeys simultaneously on one Saver Pass.
Maximum 5 people can travel together on one Saver Pass. It might be wise in some situations to buy 2 Saver Passes for 5 people: one for 2 people and one for 3 people.