Any type of small screw driver or other flat, slender metal object that will fit through the opening can be used to release the mounting bracket on each side of the oven. I assume that you have the model of Kenmore oven with the mounting brackets as shown in the image below. These Kenmore ovens have model numbers beginning with 790. . .
Be sure that you
shut off the breaker
to disconnect electrical power before pulling the oven out of the cabinet.
If you need more help or have a different type of Kenmore oven, resubmit your question with additional details and the full model number of the wall oven.