From: Rabbi Moshe Sofer
To: Unknown recipient
On the first day of Rosh Hashanah, the ba'al korei completes the entire Torah portion by the fourth aliyah, leaving nothing for the fifth. The Chasam Sofer rules that continuing into the Akeidah is correct, since it is thematically connected to Rosh Hashanah.
Source: Shu"t Chasam Sofer OC §169