Hi @Pavan rishi,
Whilst what you're requesting could be implemented via a Business Rule, from a Process perspective and best practice, I would encourage you to review and question the requirement.
(It's a case of just because something can be done, it doesn't mean it should).
When a child incident is created, whilst it is related, the process is synchronized by the Parent Incident to Child Incident, not the other way around. Additionally, should multiple incidents be created and associated, this also needs to be factored in, hence the parent relationship synchronization.
See the following link: https://www.servicenow.com/docs/bundle/xanadu-it-service-management/page/product/incident-management...
Another point to note, an incident should be Resolved primarily giving the caller the ability to Accept or Reject the Resolution. OOB (Out Of Box) an incident will be auto closed if no response or acknowledgement is received when an Incident is Resolved.
Please note however, the child Incident will also follow this Resolution process and may also requires confirmation from the caller or auto closure.
To help others (and for me to gain recognition for my efforts), please mark this response correct by clicking on Accept as Solution and/or Kudos.


Thanks, Robbie
