How to Call Ajax Function in PreSaveAction without any dependencies

PreSaveAction_AjaxCall.js

var G_IsUpdatePending = true;

function PreSaveAction(){
	AssignQuarter();
	
	if (G_IsUpdatePending){
		var dutyStation = GetSelectedTermText('Office')
		if (dutyStation){
			ShowDialog();
			$.when(AddCountryToField('Office','Country_','Region_')).then(function(){
				G_IsUpdatePending = false;
				HideDialog();
				SubmitForm();
			});
			returnValue = false;
		}
		else{
			returnValue = true;
		}
	}
	else{
		G_IsUpdatePending = true;
		returnValue = true;
	}
	return returnValue;
}

function SubmitForm(){
	if ($("INPUT[value='Save']").length > 0){
		$("INPUT[value='Save']").first().click();
	}
	else{
		$("INPUT[value='Check In']").first().click();
	}
}

function GetSelectedTermText(fieldName){
	var selectedTerm = document.getElementById(fieldName+"_$input").value;
	if (selectedTerm && selectedTerm != "") {
        selectedTerm = selectedTerm.split('|')[0];
    }
    return selectedTerm;
}

function AssignQuarter(){
	var currentMonth = $.GetFieldControl("Month").val();
	var qValue = "";
	if (currentMonth == "January" || currentMonth == "February" || currentMonth == "March"){
		qValue = "Q1";
	}
	else if (currentMonth == "April" || currentMonth == "May" || currentMonth == "June"){
		qValue = "Q2";
	}
	else if (currentMonth == "July" || currentMonth == "August" || currentMonth == "September"){
		qValue = "Q3";
	}
	else if (currentMonth == "October" || currentMonth == "November" || currentMonth == "December"){
		qValue = "Q4";
	}
	$.GetFieldControl("Quarter Required Field").val(qValue);
	
}