I came to the Prophet ﷺ and said, "Messenger of Allah, I have embraced Islam and I am married to two sisters."The Messenger of Allah ﷺ said to me, "Divorce whichever of them you wish."
حدثنا يونس بن عبد الأعلى حدثنا ابن وهب أخبرني ابن لهيعة عن أبي وهب الجيشاني حدثه أنه سمع
أتيت النبي ﷺ فقلت يا رسول الله إني أسلمت وتحتي أختان قال رسول الله ﷺ لي طلق أيتهما شئت
Graded hasan. Abu Dawud narrated it in the chapter on divorce, in the section on one who embraces Islam while having more than four wives or two sisters, hadith 2243, from the hadith of Abu Wahb with similar wording. Tirmidhi graded it hasan, hadith 1130, and Ibn Hibban graded it sahih. The hadith has other routes of transmission in Tabarani's al-Kabir, 18/328, 329, and elsewhere.