From Sahih Muslim (Hadith 2905):
Ibn Abbas reported that Duba'a bint al-Zubair b. 'Abd al-Muttalib (Allah be pleased with her) came to Allah's Messenger (ﷺ) and said:I am an ailing woman but I intend to perform Hajj; what you command me (to do)? He (the Holy Prophet) said: Enter into the state of Ihram (uttering these words) of condition: I would be free from it when Thou wouldst detain me. 'He (the narrator) said: But she was able to complete (the Hajj without breaking down)
Reference: Muslim 2905