Iphone 4 - Is it possible to change to a different carrier?

I have iphone 4 non jailbreak, with koodo as a carrier paying $35/month.

I wanna switch to mobilicity but i can't unless i pay out my phone since, this phone is 3-year term, and its been less than a year. However, i heard that if you jailbreak your phone you can change carrier. Is this possible?

The reason i want to switch carrier is because mobilicity is cheaper and gives more unlimited features for a cheap price over koodo.

The phone has to be unlocked in order to use it with a different carrier.

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