In the early years, if a child chooses cereal for breakfast, she gets cereal. She can choose not to eat it and be hungry. No one starts the waffles or the eggs after the cereal has been served just because the little darling changed her mind. Such a simple lesson teaches children that their choices will have a consequence. When choices do not affect or inconvenience other people, a change of mind can be acceptable.
Children can also learn that there is a time limit for decisions.
If they are allowed to dawdle and to change their minds every other second, the process becomes a game for attention. The way to stop such attention-getting behavior is to set a time limit for the decision. You decide before I count to 10. If the child refuses, the parent makes the decision. Next time, the child will decide.