I was present when Muawiya asked Zayd bin Arqam, "Did you witness two Eids falling on the same day with the Messenger of Allah ﷺ?"He replied, "Yes. He prayed the Eid prayer at the start of the day, then granted a concession regarding the Friday prayer, saying, 'Whoever wishes to gather for it may do so.'"
حدثنا عبد الرحمن حدثنا إسرائيل عن عثمان بن المغيرة
شهدت معاوية سأل زيد بن أرقم شهدت مع رسول الله ﷺ عيدين اجتمعا قال نعم صلى العيد أول النهار ثم رخص في الجمعة فقال من شاء أن يجمع فليجمع
Its chain of transmission is daif due to the obscurity of Iyas bin Abu Ramlah Shami. The hadith was narrated by Abu Dawud 1/281, no. 1070, Nasai 3/194, Ibn Majah 1/415, no. 1310, and Darimi 1/459, no. 1612. Hakim graded it sahih 1/288, and Dhahabi agreed with him.