In rare situations a component may want to change the props of a component that it doesn't own (like changing the className of a component passed as this.props.children). Other times it may want to make multiple copies of a component passed to it. cloneWithProps() makes this possible.
ReactComponent React.addons.cloneWithProps(ReactComponent component, object? extraProps) #Do a shallow copy of component and merge any props provided by extraProps. Props are merged in the same manner as transferPropsTo(), so props like className will be merged intelligently.