I totally agree with Britanica on how to lighten a too-dark color.
A normal shampoo or even a volumizing shampoo, which blows open the cuticle to help speed up the color fade, will help. Using hot water will also help. Blow drying with the highest heat also helps to fade the color to a lighter hue.
Be sure to finish with a cool/cold rinse to lock in the color. Also, the color will fade quickly over time.