Als je dat nummer nu niet meer hebt dan kan dat niet meer. Na beëindiging van een abonnement kan een nummer nog 1 maand teruggehaald en daarna gaat het in quarantaine en na maximaal een half jaar kan een andere klant dit krijgen bij zijn abonnement.

I mean, I have currently a subscription with a kpn mobile number. But also a lycamobile number. I no longer need the lycamobile service. But will like to keep the lycamobile number as my kpn number instead. I have it as my contact number for a lot of places and don't want to lose it. 

Is changing the kpn number to the lycamobile number possible?

I don't know if this is possible. For that we have to wait for a kpn moderator.

Other possibility:

A new subscription at kpn and porter your Lycamobile number to that.

Your current subscription can be ended as soon as the first 1 of 2 years are ended. 

After that you only have de “new” subscription with the former lycamobile number.

Sorry for faults. My English is a bit rusty.

Hello @Tamara Reid, it is possible to change your KPN number to your now Lyca number.
If you contact KPN and ask for a number change and tell the agent that you want to port your Lycamobile to the KPN subscription.