Just contact KPN and tell them u want to quit with your postpaid, they will change your current simcard into a prepaid card with the same number.

However, you can only ask this if your postpaid contract is close to expire or already have expired.

You can't use a subscription (abonnement)?

Because the easyist is:

1: take over the subscription from your employer. kpn.com/contractovername

2: If you don't wan't a subscription then you can change your subscription into a prepaid connection. For that you can call customerservice (klantenservice 0800-0402).

Hello, Thank you for your answer! 

Can you please suggest the best way to reach out to KPN regarding this? I tried contacting over the phone but it didn't go well. and that's why I decided to use this forum.

Can this be done online? (Especially uploading the NOC document from my company)

OR

You suggest me to visit a KPN store?

You suggest me to visit a KPN store?

I think that's most easy. Both party's must attend. So some-one from your employer who is responsible for telecom in the business must come to.

A KPN-moderator from this forum can't do it infortunataly. They, and the volunteers here, can only advise you.