Is there a possible way to somehow extract users principal names by a given pattern? or somehow check the uniqueness of the UPN in targeted ADDS. Any suggestions would be appreciated!
like it happened in script VI_AE_BuildCentralAccountGlobalUnique:
'fill existing addresses in a list 
 Dim existing As New List(Of String)
 Dim dummy As New Object()
 Dim dummyPerson As ISingleDbObject
 dummyPerson = Connection.CreateSingle("Person")
 Dim pattern As String = "%" & Lastname & "%"
 Dim myObjectKey As New DbObjectKey("Person", uid_person)
 Dim accountName As String
 Dim objectKeyString As String
 Dim objectKey As DbObjectKey
Using rd As IDataReader = CType(dummyPerson.Custom.CallMethod("SearchCentralAccount", pattern), IDataReader)
While rd.Read()
accountName = rd.GetString(rd.GetOrdinal("AccountName"))
 objectKeyString = rd.GetString(rd.GetOrdinal("ObjectKeyPerson"))
If Not String.IsNullOrEmpty(objectKeyString) Then
 objectKey = New DbObjectKey(objectKeyString)
'only addresses which not belong to the actual employee will be considered
 If myObjectKey.Equals(objectKey) Then
 Continue While
 End If
 End If
existing.Add(accountName)
 End While
 End Using