Save: function(component, event, helper) {
    var conObj = component.get("v.contactList");
       conObj.AccountId = null ;
    if(component.get("v.selectedLookUpRecord").Id != undefined){
      conObj.AccountId = component.get("v.selectedLookUpRecord").Id;
    }
    if (helper.validateRequired(component, event)) {
        var action = component.get("c.saveContacts");
        action.setParams({
            "ListContact": conObj
        });

<aura:attribute name="selectedLookUpRecord" type="sObject" default="{}"/>

<td>
        <c:customLookup objectAPIName="account" IconName="standard:account" label="Account Name" selectedRecord="{!v.selectedLookUpRecord}"/>
    </td>