How do I reset a UI Button's color to it's 'normal' state.

My game has a UI Panel containing child UI Buttons using “Color Tint” states to provide player interface feedback when selecting game options. Buttons handle in-game state changes automatically, however when the player requests a game restart previously pressed buttons in the button pressed state transition to the highlighted state rather than normal state. How do I reset all the buttons to the normal state using C# code.