C# - How To Return Two Different Views From The Same Action In .NET MVC

I have two views which will both use the same Controller method:

//webServiceController.cs

//The actual method is about 40 lines of code. Truncated for readability.
public ActionResult Index()
{
object i = new List<WebServiceMethod>(); [code].....

The second view is a quick'n'dirty conversion to JSON so that I can do magical AJAX tricks with the data:

<%
// AjaxGetServiceData.aspx

// Convert web service response object into JSON for AJAX.
var jss = new System.Web.Script.Serialization.JavaScriptSerializer();
Response.Write(jss.Serialize(Model));

%>

I'd created a duplicate of the Index() method and called it AjaxGetServiceData(), but that defeats the purpose of MVC.

Resolution:I didn't ask my question very well, as evidenced by a 5-10 minute discussion I just had with a coworker about this very topic. He kept asking me the same question that many users on this page asked me: "How does the controller know which view to return?" I responded, "That's what I'm trying to figure out." I was trying to get the method to return a different view (or Json output) when AJAX was the requester. A string argument in the method was my solution.

This is what I ended up using to get my desired effect:

public ActionResult Index(string isJSON = "no")
{

/// ...All the code from before...[code]....

Then, when I want the JSON version, in my AJAX request I specify the URL as /MyController/Index/?isJSON=yes When I want my pretty table view, I just use /MyController/