Sahih Muslim Book 7, Hadith Number 2760.

Chapter : Permissibility of entering into the state Ihram conditionally due to illness.

Ibn Abbas (Allah be pleased with him) reported that Duba’a intended to perform Hajj and the Apostle of Allah (may peace be upon him) commanded her (to enter into the state of Ihram) with condition. She did it in compliance with the command of Allah’s Apostle (may peace be upon him).