override templateurl for component in angularjs1.5

Question

I want to override the templateurl of the component.

Lets say I have below component.

angular.
module('myApp').
component('greetUser', {
template: usertemplate.html,
controller: function GreetUserController() {
this.user = 'world';
}
});

I am want to override this component so that whenever they access geet-user my custom template.html. It tired by re declaring the same but it is throwing an error saying two selector for geet-user. Any suggestions?

Thanks,In Advance. Sree.