What is the ruling when a person enters the state of Ihram on behalf of two principals?

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If two individuals appoint one person to perform a ritual (Hajj or Umrah) on their behalf, and that agent enters the state of Ihram for them both, the Ihram is valid only for the agent himself and not for the two principals. This is because the ritual cannot simultaneously be valid for both principals, and neither principal has precedence over the other.