How to stop the rename the cn again if it had meet the condition

How to stop to rename the CN in Active directory if running the script.

This is my script:

$objSearch = New-Object DirectoryServices.DirectorySearcher
$dateNow = Get-Date
$DomainDNS = "server2008.server1.com" #server 2008
$ADpath = [ADSI]"LDAP://$DomainDNS/ou=power shell test,dc=server1,dc=com"
$objSearch.Filter = '(&(objectClass=user)(objectCategory=person)(!samaccountname=user1))'
$objSearch.SearchRoot = $ADpath
$objSearch.PageSize = 1000
$objSearch.SearchScope = "subtree" 
$objResults = $objSearch.Findall()

write-host 'objResults: ' $objResults

foreach($objResult in $objResults){  

$objuser = $objResult.GetDirectoryEntry()
$name = $objuser.cn
write-host "name:" $name

if (($objuser.cn -notcontains "DA$name")){
    $changeName = "DA" + $name
    write-host 'CHANGE NAME: ' $changeName
    $objuser.rename("cn=$changeName")
    $objuser.CommitChanges()
  }

  else {
    continue
  }

}

The result I get is :

what I want the result is: