CmdID

CmdID / PowerShell / Cmdlets / Set

Set-OMEMessageRevocation

Use the Set-OMEMessageRevocation cmdlet to revoke Microsoft Purview Message Encryption for a message. Exchange PowerShell reference

From the Exchange PowerShell reference 2 parameters Its page in the reference

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Parameters

2 in the Exchange PowerShell reference
-MessageIdThe MessageId parameter specifies the message based on the value the Message-ID header field.
-RevokeThe Revoke parameter specifies whether to revoke encryption for the message.