Wait it out and don't give them anything else. If they're really subborn and after days they still haven't eaten, then you might change it. Don't cater to their pickiness, though unless they are really not eating.
First, take the dog to the vet to make sure it is healthy, dogs go off food when they are sick. If the vet can find no health problems, pick one brand of premium kibble and stick to it. Do not keep changing their food, it just encourages the picky nature. Two times a day, fill the dog's dish with the appropriate amount of food, put it down on the floor, and give the dog 20 minutes to eat it. If it doesn't eat the food within the 20 minutes, pick it up, put the food back in the food bag/bin, and wait till the next feeding. Just make sure the dog has fresh water at all times. If you stick with it for a week, the dog will learn that you aren't going to spoil it by swapping it's food every 2 or 3 days, and if it wants to eat, it'd better eat before the opportunity is missed. A dog will not starve to death if it goes a few days (or even a week, honestly) without food. Even a picky dog should nibble on kibble within a day or two of having no other options. I have a friend who was having a problem with her picky akita, and she left his food there for about 10 minutes, then picked up his dish and gave it to one of the other dogs she has and let it eat the food right where the akita would have to watch. After that, the akita decided maybe his food wasn't so bad after all ;)
Maybe try adding water to the kibble. My pup was not eating his food and now that I have started adding the water he eats. He still doesnt eat it within 15 minutes of putting it down--but I don't really care about that--I just put it down 2x a day and eventually he eats it all.