“The Messenger of Allah (ﷺ) commanded us to bring them (the women) out on the day of Fitr and the day of Nahr.” Umm ‘Atiyyah said: “We said: ‘What if one of them does not have an outer covering?’ He said: ‘Let her sister share her own outer covering with her.’”
Sunan Ibn Majah Book 5, Hadith 505