Nej. You can change/delete it till Midnatt (1 minute before), and not any later.

But the general advice here is to do it as late as possible-there is a constant stream on this forum of people who did not and now regret it. Also: make REServasjoner not via app-but directly with railways=gives you much more chance, mindre priser och less stress. Then you do not need to activate it early either.

Don't activate your pass until just before boarding your first train. Read more below.

When you choose the start day of the validity of the pass, the first day of the validity period is automatically made a travel day, even if you don't enter a journey, the advice is therefore not to activate the pass before the first travel day as you only can deactivate the pass before 00.00 on the day the validity starts.

If you have activated the pass in advance and something happens on your first travel day before you have boarded the train that prevents you from starting the trip, then you can't deactivate the pass.

It can be wise to test to activate the pass, with a start date in the future, to see that it works, and then immediately deactivate the pass.

Thank you mcadv and AnnaB, tusen takk!

Important and extremely useful info

Thanks!

Det sker regelbundet att personer förlorar resdagar för att de aktiverat passet i förväg och sedan blir sjuka på avtesedagen. Eller att de har ett flexi pass och har kopplat sina "journeys" till passet i förväg och sedan sker något som gör att de inte kan åka just den dagen. 

Hoppas att du får en god tur i Europa.