Assertion: change | /r/HasProperty | required
Facets:
Source sentences:
text: Important elements of a change request are an ID, the customer (ID), the deadline (if applicable), an indication whether the change is required or optional, the change type (often chosen from a domain-specific ontology) and a change abstract, which is a piece of narrative (Keller, 2005).
text: They may also specify what happens if a change contrary to the rules is required, such as restarting the freeze period.