If you mean that you want to ditch your old phone number and get a new 089 number then you'll have to contact 48 support to ask them if they can facilitate this.
See the link in my signature below or email them at support@48months.zendesk.com
If they can't then you can just get a new 48 SIM and set up from scratch as a new user and you'll get a new 089 number that way.
