Child Incident state is not moving from new to in-progress when parent incident state changed to In-Progress.

When a parent incident is moved to In Progress the child incident associated is not moving to 'In progress ' state. The sync between parent and Child is not working.

• The parent and child Incident state synchronization is controlled by the business rule " Sync Child Incident State ', refer the below documentation which explains the same
• https://docs.servicenow.com/csh?topicname=c_IncidentManagement.html&version=latest
• This Business rule comes as part of the plugin ' Incident Management Best Practice - Kingston plugin (com.snc.best_practice.incident.kingston) '
• If you do not have this plugin activated the parent-child incident state sync does not work because of the missing business rule which controls the synchronization
• This sync between parent and child works for the states as described in the below doc :
  https://docs.servicenow.com/csh?topicname=parent-child-state-sync.html&version=latest
• If you do not want to install the plugin, they need to customization the synchronization to work and write business rule based on the requirement

STEPS TO REPRODUCE:

• Login to the affected instance
• Open an Incident which has child incidents associated
• Change the Parent incident state from New to In progress
• The child incident state is still in new and is not moving to 'In progress '