Help me !!! change the direction of a projectile

I was doing a 2D platform game and I needed to create a mechanic, in this game, the player launches a projectile and when the projectile collides with a specific object, the projectile changes its direction to another object and I do not know how I can do this

Try to look at this.
Hello

http://www.theappguruz.com/blog/collision-detection-without-rigid-body-in-unity