If someone omits the sa'i between Safa and Marwah, what is required of him?

Hasan says about the person who abandons the Sa'i between Safa and Marwah that a sacrifice (dam) becomes obligatory upon him.

Hazrat Dawood bin Asim came for Hajj or Umrah and omitted the Sa'i between Safa and Marwah. Hazrat Ata said: "Offer a sacrifice," and Hazrat Tawus said: "Enter as one performing Umrah."

14782 - Tawus said: Enter as a Mu'tamir (performing 'Umrah).

Hazrat Abu Ma'shar and Ibrahim state that if a pilgrim forgets to perform Sa'i between Safa and Marwah during Hajj, then performing (another) Hajj becomes obligatory upon him, and if he is performing Umrah, then he must perform (another) Umrah, and nothing except the Sa'i between Safa and Marwah will suffice for him.

14784 - From Abu Ma’shar, from Ibrahim, they said: If one forgets (the sa’i) (1) between Safa and Marwah while performing Hajj, then Hajj is due upon him; and if he is performing ‘Umrah, then ‘Umrah is due upon him, and nothing suffices him except the sa’i between them.