The Messenger of Allah (ﷺ) restored his daughter Zaynab to Abul'As on the basis of the previous marriage, and he did not do anything afresh.

Muhammad b. 'Amr said in his version: After six years. Al-Hasan b. 'Ali said: After two years.
Sunan Abi Dawud Book 13, Hadith 66
← Previous Hadith A woman embraced Islam during the time of the Messenger of Allah (ﷺ); she then married. Her (former) husband then came to the Prophet (ﷺ) and said: Messenger of Allah, I have already embraced Islam, and she had the knowledge about my Islam. The Messenger of Allah (ﷺ) took her away from her latter husband and restored her to her former husband.

Sunan Abi Dawud Book 13, Hadith 65 Next Hadith → I embraced Islam while I had eight wives. So I mentioned it to the Prophet (ﷺ). The Prophet (said) said: Select four of them.

Abu Dawud said: This tradition has also been narrated to us by Ahmad b. Ibrahim from Hushaim. He said: Qais b. al-Harith instead of al-Harith b. Qais. Ahmad b. Ibrahim said: This is correct, i.e. Qais b. al-Harith.

Sunan Abi Dawud Book 13, Hadith 67