How can I automatically update service or help desk request status after a customer response?

You create a trigger in Application Composer on the Message child object of either the Service Request parent object or the HR Help Desk Request object

Here's how:

1. Create a new sandbox or open an existing one. From the sandbox Tools menu, select Application Composer.
2. In the object panel, expand Standard objects, then HR Help Desk Request (or Service Request), then the Message child object, and then select Server Scripts.
3. Click the Triggers tab, then click Add a new Trigger.
4. From the Trigger drop-down list, select Before Insert in Database.
5. Enter an error message in case the validation fails.
6. In the Trigger Definition field, paste the following Groovy script:
   Note: Change CUST_REPOND in the script to your own status value.

   def parentSR = ServiceRequest
   def msgSource = SourceCd
   def msgChannel = ChannelTypeCd
   def parentStatus = ServiceRequest?.StatusCd
   def msgType = MessageTypeCd
   
   
    
   if (msgSource =='ORA_SVC_INBOUND_MSG' && msgChannel =='ORA_SVC_EMAIL' &&
   msgType == 'ORA_SVC_CUSTOMER_ENTRY' && ParentMessageId !=null)
   
   parentSR.setAttribute('StatusCd', 'CUST_RESPOND')

7. Click Save and Close.