The ruling on changing the ihram intention depends on the direction of the change. Adding Haji to an existing Umrah intention (converting from ifrad Umrah to qiran — combining Haji and Umrah) is boleh menurut jumhur ulama, provided this is done before beginning the tawaf of Umrah. Once tawaf has begun, the rites of Umrah have started and the intention cannot be changed according to most scholars. Sheikh Ibn Baz confirmed this ruling, noting that Nabi (shallallahu alaihi wa sallam) himself performed qiran, combining Haji and Umrah in a single ihram.
The more debated question is whether a jamaah haji who entered ihram for Haji alone (ifrad) can change their intention to Umrah (converting to tamattu). This is based on the famous incident during the Farewell Haji when Nabi instructed his companions who had entered ihram for Haji but did not have a sacrificial animal (hadyu) to change their intention to Umrah, perform tawaf and sa'i, cut their hair, and exit ihram, then re-enter ihram for Haji on the 8th of Dhul-Hijjah. Sheikh Ibn Uthaymeen held that this option remains available to jamaah haji today, not limited to the companions alone.
The Permanent Committee ruled that a jamaah haji may change from Haji to Umrah (becoming mutamatti') as long as they have not begun the rites of Haji. However, the Hanafi and Maliki schools generally do not permit downgrading from Haji to Umrah once ihram for Haji has been assumed. If a jamaah haji is unsure of their intention, they may make a conditional intention (ishtirat) at the time of entering ihram, saying: 'If something prevents me, my place of exit from ihram is wherever I am stopped.'