Migrating from LCS to Lync is not possible without before going through all intermediate versions.
So one way is to start over. For that first we need to remove LCS attributes:
Here it is a simple script with Quest’s ActiveRoles Management Shell for Active Directory
$list = Get-QADUser -ObjectAttributes @{“msRTCSIP-PrimaryHomeServer”=’CN=RTC Services,CN=Microsoft,CN=LCS-Servers,CN=Computers,DC=example,DC=com’} -SearchRoot ‘example.com/Users’
foreach ($item in $list)
{
Set-QADUser $item -ObjectAttribute @{“msRTCSIP-PrimaryHomeServer”=$null}
Set-QADUser $item -ObjectAttribute @{“msRTCSIP-PrimaryUserAddress”=$null}
Set-QADUser $item -ObjectAttribute @{“msRTCSIP-UserEnabled”=$null}
Set-QADUser $item -ObjectAttribute @{“msRTCSIP-IsMaster”=$null}
}
