cf session timeout when only using ajax calls

I have a cf9 app that just has a few ajax calls. They are from a prev/next button and if a person just sits and presses the next button for 20 minutes they get timed-out because our 20 minute session timeout setting. What can I do to reset the cf session timeout when they click on the "next" button?

$(document).ready(function() {

  $("#PaymentPlanTrackingListNextButton").live ('click', function() {

    $.get('payment_plans_tracking_list.cfm',

    {

      PaymentPlanTrackingAdvisor:$("#PaymentPlanTrackingAdvisor").val(),

      PaymentPlanTrackingDueDateStart:$("#PaymentPlanTrackingDueDateStart").val(),

      PaymentPlanTrackingDueDateEnd:$("#PaymentPlanTrackingDueDateEnd").val(),

      PaymentPlanTrackingListCurrentPage:parseInt($("#PaymentPlanTrackingListCurrentPage").val()) + 1

    },

    // Sends to div id=PaymentPlanTrackingList

    function(data,status) {

      $("#PaymentPlanTrackingList").html(data);

      $("#PaymentPlanTrackingStatus").html("");

    })

  })

})