Iyas bin Abi Ramlah al-Shami narrates that he was present with Sayyiduna Mu'awiyah bin Abi Sufyan (may Allah be pleased with him) when he was asking Sayyiduna Zayd bin Arqam (may Allah be pleased with him). He said: "Were you present with the Messenger of Allah (peace and blessings be upon him) on an occasion when two Eids fell on one day?" He said: "Yes." He asked: "Then what did he (peace and blessings be upon him) do?" He said: "He (peace and blessings be upon him) offered the Eid prayer, then granted a concession regarding the Friday prayer and said: 'Whoever wishes may offer the Friday prayer.'"
Hadith Referenceالمعجم الكبير للطبراني / باب الزاي / 5101