You can't change the Ip-address.Ip-addresses are provided by Internet Service Providers(ISP)... If it's static Ip-address means you cannot change it.You can change only Dynamic ip-address ......Reset the modem means a new ip-address will assign it's Dynamic Ip-address.You can also use the proxy server to hide the original ip ...It will show the fake ip-address.Before and after hiding ip-address or changing it you can check the ip-address at
Ip-Details.com