In itself Knockout does not do this for you automatically, so
- you do it manually like your jsfiddle
- you use the Knockout.Mapping plugin which is designed for this scenario: convert plain JavaScript objects to objects with observable properties.
So in your example you just need to write:
this.changeRequestLocations = ko.mapping.fromJS(BaseModel.changeRequestLocations);
and the mapping plugin will convert your location
array into an observable array.
Demo JSFiddle.