It depends on what kind of “cancellation” you want to pursue.
If you wish to “terminate” the agreement, you can declare your intention not to perform the contract anymore. The other party can treat this as a breach of contract, and you will become liable to compensate them for non-performance.
If you believe that there was no true contract between you in the first place (such as the other party misrepresenting something before you signed) then you can try for rescission, where you are returned to the position you were before making the agreement, and no damages are liable.