the email notification that kace has are a bit limited and the instruction that you can use more even. i wanted to send an email notification to the submitter when whoever (owner or not) add a note in his ticket, but i wanted to send just the las comment, not the whole conversation neither the person who is writting or other information, just the new added comment. So my rule is this:

->Select SQL

SELECT HD_TICKET.ID as ID,HD_TICKET.TITLE as TITLE, 
           E.FULL_NAME as SOLICITANTE,
           DONO.FULL_NAME as ATENDENTE, 
           E.EMAIL as EMAIL_SOLICITANTE,
           HTC.COMMENT AS COMENTARIO,
           S.NAME AS ESTADO
        
FROM(HD_TICKET, HD_PRIORITY, HD_STATUS, HD_IMPACT, HD_CATEGORY) 
left join USER DONO on DONO.ID = HD_TICKET.OWNER_ID 
LEFT JOIN USER E on E.ID = HD_TICKET.SUBMITTER_ID
        LEFT JOIN HD_STATUS S ON (HD_TICKET.HD_STATUS_ID = S.ID)
    
inner Join ( Select TC.HD_TICKET_ID, max(TC.ID) IDFilho from HD_TICKET_CHANGE TC 
inner join HD_TICKET_CHANGE_FIELD F on ( F.HD_TICKET_CHANGE_ID = TC.ID) 
Group by TC.HD_TICKET_ID ) X on ( X.HD_TICKET_ID =  HD_TICKET.ID )
                
inner Join HD_TICKET_CHANGE_FIELD F on ( F.HD_TICKET_CHANGE_ID = X.IDFilho)
inner Join HD_TICKET_CHANGE HTC  on ( X.IDFilho = HTC.ID)
 
where  
   HD_PRIORITY.ID = HD_PRIORITY_ID
   and HD_STATUS.ID = HD_STATUS_ID
   and HD_IMPACT.ID = HD_IMPACT_ID
   and HD_CATEGORY.ID = HD_CATEGORY_ID 
   and F.FIELD_CHANGED = 'COMMENT' and
   HTC.USER_ID  != HD_TICKET.SUBMITTER_ID 

group by HD_TICKET.ID


->Active the checkbox to send email

Title:[$id] $title - $estado
Email: EMAIL_SOLICITANTE
Message: 

Prezado(a) $solicitante,

Uma nota foi adicionada ao seu chamado:

$comentario

Corpo do chamado:
http://yourservicedeskdirection/adminui/ticket.php?ID=$id

Atenciosamente, 


Hope it is useful!!!