Parent cases are cases that are linked to other cases which are called child cases. This linking can be useful for grouping, managing, and tracking cases more efficiently. ServiceNow treats parent-child relationships as one-way synchronization events where changes that are made to fields of a parent record get automatically copied down to all child cases (but not the other way around). The system has a defined set of these fields that, once updated, have their new values automatically copied down to the same field for the child cases. These fields include the case status field, comments, work notes, and priority. This allows agents to rapidly communicate changes to child cases simply by updating a specific field of the parent case. One example where this might be useful would be if you encountered a major incident along with many other smaller incident cases. The major incident could be set as a parent case to these incidents. Doing so would allow you to update, say, the status field of these individual cases all at once just by updating the parent.
Whenever a somebody changes the value of an enabled field in a parent case the system will automatically also make that exact change on that exact field on each of that parent's child cases. No other fields will get updated exact for the one that is changed in the parent. What is tricky is that, based on the value of the child's status field, this behavior sometimes won't happen. The status field of any case record is always one of either New, Open, Awaiting Customer Action, Solution Proposed, or Closed. When a record is closed it gets locked for editing which means that its fields cannot be changed. So, it makes sense then that closed case records will not receive updates because their fields can't get updated. What's tricky is that this happens to also be true for child cases with a status of "Solution Proposed". So, to clarify, if a case is either "Closed" or "Solution Proposed" then it will not receive any updates from its parent case. This restriction does not apply to parent cases meaning that a parent case can still send down changes to its children if it is on "Solution Proposed".
Follow these steps to set a case as a parent of another case:
When a parent case's field is updated that update will propagate down to its child cases (assuming that the updated field is enabled for parent cases). Here's how to do that:
A child may have only one parent case at a time. This parent field can be set and reset at any point.
A case may be a child of a child. Synchronization cascades down from the parent. Descendants receive synchronized changes provided their parent does. Thus as long as every case in the chain can be synchronized it follows that any parent change will propagate down the youngest child.
Synchronization only occurs downward. A parent case that is also a child of another parent case only updates its child cases - never its parent case.
When a parent case is updated, only fields that have been altered since the last change will be synchronized to children.
The chain of descendant cases cannot be circular. That is, a parent case cannot be declared a child of one of its descendants.
In order for a change to a parent case to be reflected in child case the user must select "Update" or "Save and Stay" in case view. For any given field, if the parent and child do not match, then synchronization will only happen if the field in the parent record changed before the update.