It is narrated from Sayyiduna Abu Umayyah (may Allah be pleased with him) that he said: "I came to the Prophet (peace and blessings be upon him) while he (peace and blessings be upon him) was eating. He (peace and blessings be upon him) said: 'Come (and eat).' I said: 'I am fasting.' He (peace and blessings be upon him) said: 'Come closer, I will tell you: indeed, Allah Almighty has relieved the traveller of fasting and of half the prayer.'"
No one narrated this hadith from Ali bin Zayd (may Allah have mercy on him) except al-Khalil (may Allah have mercy on him), and Hisham bin Ammar (may Allah have mercy on him) is alone in narrating it from him.