Sprite Swapping help

Ive just started to create my first 2d game, im decent at 3d games, but I want to know how to change my sprite after I press a button, eg. "D" or "A"

Ive got this far :

 public Sprite right;
 public Sprite left;
 
 void Update(){
          if(Input.GetKey("D")){
              Getcomponent(SpriteRenderer)//Then I want to call on it to select the Sprite "Right"

          if(Input.GetKey("A")){
              Getcomponent(SpriteRenderer)//Then I want to call on it to select the Sprite "Left"

           }
 
 }

But Then how do i call upon the sprite itself to be changed depending on whether i choose right or left? help?:/