Original: The eyewall collapsed somewhat, and Helene weakened slightly to a Category 2 hurricane, where it leveled off for about 48 hours until September 20 due to a lengthy eyewall replacement cycle and an elongated cloud pattern.
Simplified: The eyewall collapsed somewhat, and Helene weakened into a Category 2 hurricane, where it levelled off for about 48 hours until September 20 because of a lengthy eyewall replacement cycle and a stretched out cloud pattern.