Will unlocking an iPhone change its IMEI number?

I bought a phone off of Kijiji (like an idiot…) and found out that it has been blacklisted. I don't want the money I spent on it to go to waste, so I was wondering that if I were to have the phone unlocked (so I could use it with any service provider) if that would allow me to use it. If not, is there any other way for me to be able to use this phone? Regardless it needs to be unlocked.

Added (1). It is an iPhone 5 locked to Fido. It has been blacklisted, meaning registered as lost/stolen. Any answers on how I can use this phone would be great!

Unlocking your phone doesn't change your IMEI number. For unlocking your iphone there are two types available, Factory unlock & Normal unlock. You should opt for a factory unlock, that enables you to upgrade your ios whenever a new one is available. It is unknown which iphone your using so i can't tell you if it can unlocked. The ios 7 i.e. Iphone 5 S / C have just been recently cracked so i don't forsee any problems for you. You should definitely make use of the phone that you have bought.

By blacklisted do you mean registered as loss or stolen. If yes then this phone will not be able to be unlocked unless the original owner claims it. A lot of people do this scam on ebay where they claim on the insurance then sell it. So check the true status of the phone first before you spend anymore money on it