How to swap 2 different component views in Salesforce Lightning?

You can do this using lightning event.Lightning event is best way communicate between two components.

You need to follow these steps for these type of scenario:

1. Create a main component which will be use as container for two components.
2. Let suppose you want to swap from component A to component B.First create view for component A in main component.
3. When you want to swap from component A to B fire an event from A that will be handled bu main component.
4. Main component will destroy component A and will create Component B.

Hi,

You can use the standard methods for lightning to swap components. $A.createComponent() method to create another component from one component and component.destroy () method to destroy the new created component.

$A.createComponent(
"c:AddAgreementComponent", // creating a component
{
"productWrapper": productWrapObj // setting the attribute of a component.
},
function(newComponent, status, errorMessage){
if (status === "SUCCESS") {
var body = component.get("v.body");
body.push(newComponent);
component.set("v.body", body);
}
}
);

Thanks