CmdID / PowerShell / Cmdlets / Set
Set-LinkedUser
Use the Set-LinkedUser cmdlet to modify the properties of an existing linked user account. Exchange PowerShell reference
From the Exchange PowerShell reference 4 parameters Its page in the reference
Parameters
-IdentityThe Identity parameter specifies the linked user.-CertificateSubjectThe CertificateSubject parameter specifies the value of the subject field of the user's digital certificate.-Confirm, -cfThe Confirm switch specifies whether to show or hide the confirmation prompt.-WhatIf, -wiThe WhatIf switch shows what the command does without making any changes.