Exiting If statement loop python

For some reason I cannot exit this loop when I change to intro = false, can anyone help as to how I'd exit this if statement. It is my menu screen, and once I click 'new game' I want it to exit the game_intro function.

This is where I define game_intro:

def game_intro():
    intro = True

    if intro == True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()

        window.fill(superlightgrey)
        fontvertical = pygame.font.SysFont("comicsansms", 100)    
        text = fontvertical.render("Connect 4", True, skyblue)
        word = (10, 1)
        window.blit(text,word)
        ButtonIntro("New Game", 340, 140, 200, 50, superlightgrey, superlightgrey, "Play")

This is where I created the button function:

def ButtonIntro(msg, x, y, w, h, ic, ac, action=None):
    mouse = pygame.mouse.get_pos()
    click = pygame.mouse.get_pressed()
    if x+w > mouse[0] > x and y+h > mouse[1] > y:
        pygame.draw.rect(window, ac, (x, y, w, h))
        if click[0] == 1 and action != None:
            pygame.draw.rect(window, lightgrey, (x, y, w, h))
            if action == "Play":            
                intro = False
                ##WHAT DO I NEED HERE TO EXIT LOOP

and this is where I call on the function:

while intro == True:
    game_intro()
print("loopexited")