Usually, you would be entitled to receive a full refund of any premium or fees you may have already paid. In respect of unit-linked policies (such as retirement plans), you might not receive the full amount if, in the meantime, the value of the investments making up the policy decreased.
If any reward or benefits, such as any benefits paid under a life policy, are paid during the cooling off period, you would be required to pay it back. In addition, refund of premium will be given as long as no claims have been made in the meantime. You would need to return your insurance schedule or certificate to the insurance company together with your intension to cancel in writing.