From Sahih Bukhari (Hadith 4398):
Narrated Hafsa:(the wife of the Prophet) The Prophet (ﷺ) ordered all his wives to finish their Ihram during the year of Hajjat-ul-Wada`. On that, I asked the Prophet (ﷺ) "What stops you from finishing your Ihram?" He said, "I have matted my hair and garlanded my Hadi. So I will not finish my Ihram unless I have slaughtered my Hadi
Reference: Bukhari 4398