getting off train before my booked station

I’ve already booked an Innsbruck to Amsterdam night train, but have since decided I’d like to get off at Cologne ( one of the stations it stops at) to explore there , instead of continuing the journey to Amsterdam.

Can I just do this, or do I need to change ticket / inform someone?

Thanks

( it’s with a global pass if that makes a difference, and I know I’ll use up another day when a do continue to Amsterdam, but that’s fine)