In general, it's not possibile to change your IP address but, eventually, you can request an additional IP address for your server or buy a new dedicated service.
There are a few occasions in which our sys administrators allow the replacement of an IP address: such as, for example, the addition of an IP address to a blacklist. If the IP was already enlisted in a blacklist before the assignment, according to a specific request and after several checks, our administrators will consider the possibility to change the IP. But if the IP has been enlisted in a blacklist after the assignment, you will have to contact the providers and ask for the the delist process by your own after the resolution of the problem on your server. In case of a "Managed" server our administrators will take care of the procedure.
Anyway, the IP change cannot be guaranteed.