What are the conditions for shortening the hair during 'Umrah?

Question:
The questioner asks: What is the ruling for one who thought that shortening the hair meant taking from scattered areas of the head, and he heard that, then exited the state of ihram? What is the ruling if he later learns that shortening the hair must be done for the whole head? What should he do now?

Answer:
He must put on the ihram garments again, then complete shortening his head. He must put on the ihram garments as they were and complete shortening the head, because it is necessary to cover the entire head with shortening, just as it is covered with shaving. Shortening is an alternative to shaving, and shaving must cover the entire head, so shortening is the same. This is a matter in which some people are lenient or rush.
Or he hears the words of some scholars that a quarter of the head is sufficient, or that this is all there is to it. There is no evidence for that. The evidence is that it is necessary to cover the entire head. Allah the Exalted said: "Shaving your heads or shortening them," meaning shortening your heads. When "head" is mentioned in a general sense, it covers the entire head. It is not restricted to part of the head. Part of the head, a quarter of the head, or half of the head is not called a head. The head is the complete head. Yes.