Change Mobile License to MVP for an existing user

I am attempting to change a user license from mobile to MVP but keep her phone number. When attempting to add the MVP license it add two number vs just the current one. This effort is because currently the soft phone only works on he mobile device. At this time we only want her to use her laptop. When attempt to make a call she get the following message: "Sorry, you can only make calls to your coworkers'...". My thoughts are to change her licensing enabling the soft phone.