Missing the standing at عرفات entirely means the حاجی has missed حج, as نبی کریم (صلی اللہ علیہ وسلم) said: 'حج is عرفات.' If a حاجی fails to be present at عرفات at any point between the afternoon (zawal) of the 9th and dawn (fajr) of the 10th of Dhul-Hijjah, their حج is not valid and cannot be completed that year. This is the unanimous position of all four schools of jurisprudence.
Sheikh Ibn Baz explained the procedure for someone who has missed عرفات: the حاجی should convert their intention to عمرہ, perform طواف around the کعبۃ اللہ and sa'i between Safa and Marwah, cut or shave their hair, and exit the state of احرام. This converts their missed حج into an عمرہ, which releases them from احرام. If the حج they missed was their واجب (first) حج, they must perform it the following year.
Sheikh Ibn Uthaymeen added that if the missed حج was a voluntary حج, there is no obligation to make it up. He also noted that a dam (sacrifice of a sheep) is required according to the Hanafi and Maliki schools for someone who missed حج and converted to عمرہ, while the Shafi'i and Hanbali schools do not require a dam for the conversion itself. The key lesson is the absolute centrality of عرفات to the حج — without it, no other rite can substitute or compensate.