@Vladan 

Yes, you can move your mobile phone do that but there a number of “ifs” & “buts". Additional conditions apply. The following webpage (in dutch) provides more details. Perhaps you know someone who can translate the dutch webpage for you ?

https://www.kpn.com/mobiel-abonnement/overstappen.htm

(Is deze informatie ook beschikbaar in engels op de KPN website ??)

@Vladan 

(To be honest: I don't fully understand your question).

You'll have to wait until your current mobile subscription has expired before it can be added to your (other) KPN subscription. As soon as your current subscription has expired the KPN can help you to move that subscription to your (other) KPN subscription.

More details (in dutch) can be found here:

https://www.kpn.com/mobiel-abonnement/overstappen.htm

Hi @Vladan! Welcome to our forum. I hope the messages above answered some of your questions.
If you want to transfer your number from a different provider you can order a subscription with “nummerbehoud” where we'll move your number.
You can place one of these orders 120 days before the end of your current subscription.

To place an order like that you can order through our website www.kpn.com/mobiel, by phone on 0800-0402, through the chat on www.kpn.com/service or by visiting one of our shops

We havent heard from you so I'm assuming this answers your question. If not, or you have any additional questions you know where to find us!