<lightning:overlayLibrary aura:id="overlayLib"/>
<lightning:button name="modal" label="Create Pet" onclick="{!c.handleShowModal}"/>

handleShowModal : function (component, event, helper) {
    var modalBody;
    var modalFooter;
    $A.createComponents([
        ["c:IFBPetCreate", {"record": component.get("v.newPet"),
                            "needsOwner": component.get("v.missingPetOwner"),
                            "isEU": component.get("v.isEuUser"),
                            "contList": component.get("v.contList"),
                            "isLead": component.get("v.isLead")}],

        ["c:ModalFooter", {"recordId": component.get("v.recordId"),
                           "newPet": component.get("v.newPet")}]
    ],
    function(components, status){
        if (status === "SUCCESS") {
            modalBody = components[0];
            modalFooter = components[1];
            component.find('overlayLib').showCustomModal({
               header: "New Pet",
               body: modalBody,
               footer: modalFooter,
               showCloseButton: false,
               cssClass: "my-modal,my-custom-class,my-other-class",
               closeCallback: function() {
                 //alert('You closed the alert!');
               }
           })
        }
    }
   );
},

<aura:component implements="force:hasRecordId" controller="CasePetList_Controller">

    <aura:attribute name="recordId" type="String" />
    <aura:attribute name="newPet" type="Pet__c" default="{'sobjectType':'Pet__c', 'Active__c':true}" />

    <lightning:overlayLibrary aura:id="overlayLib"/>
    <lightning:button name="cancel" label="Cancel" onclick="{!c.handleCancel}"/>
    <lightning:button name="save" label="Save" variant="brand" onclick="{!c.handleSave}"/>

</aura:component>

handleCancel : function(component, event, helper) {
    component.find("overlayLib").notifyClose();
    console.log('handleCancel: component: '+component);
    var action = component.get("c.setNewPet");
        console.log('handleCancel: action: '+action);
        action.setParams({
            recId: component.get("v.recordId")
        });
        action.setCallback(this, function(response) {
            var state = response.getState();
            if(state === "SUCCESS") {
                component.set("v.newPet", response.getReturnValue());
            }else{
                console.log('Problem getting new pet, response state: ' + state);
            }
        });
    $A.enqueueAction(action);
},