It's unlikely you'd be able to do this. If the IP belongs to your ISP, perhaps you can ask that they assign this IP to you. It may cost more since you'll have a static IP at that point. If the IP is not under the control of your ISP and is controlled by another ISP, then you'd have to switch ISPs possibly. If the IP is owned but not in use, there are ways to buy blocks of IP addresses, but this is an unlikely scenario for a residential customer. If you're a business customer, your ISP might be able to handle your request.