description: Reference to the List that a \"change\" list is asserting changes with respect to. package_name: hl7.fhir.uv.extensions.r5 derivation: constraint name: ListChangeBase type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/list-changeBase'} index: 1 value: choices: [valueReference] index: 3 valueReference: type: Reference choiceOf: value refers: ['http://hl7.org/fhir/StructureDefinition/List'] index: 4 package_version: 5.3.0-ballot-tc extensions: {} class: extension kind: complex-type url: http://hl7.org/fhir/StructureDefinition/list-changeBase base: http://hl7.org/fhir/StructureDefinition/Extension version: 5.3.0-ballot-tc required: [valueReference, value]