Can I add a journey on an active day ?

I could not find a precise answer to this question : most answers refer to activating the pass, but my question is whether I can add a journey on an active day (after I already completed a journey on that same day using my interrail global pass).

Here is a concrete example : I use my interrail global pass to take a train, in the morning, from Hamburg to Koln (thus the pass has been activated, and the travel day associated with this journey is active). When I arrive in Koln, I decide to go further away and take a train, in the evening, to go from Koln to Liège. The two journeys are performed on the same day but the first journey Hamburg-Koln was planned and the second journey Koln-Liège was decided on the go. Can I add the journey Koln-Liège on my pass although the day is already active ?

Mike