You must understand that when you sell a bond, you are shifting the rights to receive yields on it to the other party. So, your only gain is the price you can negotiate for the bond.
The intrinsic value of the corporate bond depends on the interest rate. The bond value tends to rise when interest rate falls, and conversely, its value falls when interest rate increases because the new bonds will offer a higher return. So, when you sell a corporate bond before maturity, its value can be more or less depending on supply and demand factors.