This slightly more complex version changes the "SMTP server" entry on all accounts.



$sMainKeyName="HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\OMI Account Manager\Accounts"
$sValueName="SMTP Server"
 
$sOldServer="xxx.yyyyyyyyyy.zzz"
$sNewServer="aaa.bbbbbbbbbb.ccc"
 
$iIndex=0
$sKeyName=EnumKey($sMainKeyName,$iIndex)
While @ERROR=0
        If ReadValue($sKeyName,$sValueName)=$sOldServer $sIgnore=WriteValue($sKeyName,$sValueName,$sNewServer,"REG_SZ") EndIf
        $iIndex=$iIndex+1
        $sKeyName=EnumKey($sMainKeyName,$iIndex)
Loop