How can I switch the direction on the drill?

In order to change the direction of torque, fully toggle the switch above the trigger into the alternative position.

"I have a domestic 450w Black & Decker electric drill that does not have a reverse switch, yet it is turning anti-clockwise. Mind you, I lent this driller to someone who returned it long ago, but now I wished to use it in lieu of the other two that I have and discovered that it has started to turn anti-clocwise with the result that the chuck unwinds. Please can i repair it as it is adequate for me.

Update (02/09/2017)

I do not know if he repaired it or not, because he passed away.

Update (02/09/2017)

Re Black & Decker drill, it only has a common switch and a sideway button which when pressed while drill is functioning will render drill functioning automatically. Again, please anyone with a correct answer? Thanks beforehand.

Update (02/09/2017)

Hi Mr Edgardo Gutierrez thank you for your answer. But my drill has a common switch."