Polymer JS passing function from one component to another?

Component A:

<polymer-element name="componentA" extends="core-ajax" attributes="onComplete">
<script>

Polymer('componentA',{
    requestCompleted: function(){
         this.onComplete();
    }
});

Component B:

<polymer-element name="componentB">
<template>
    <componentA method="GET" onComplete="{{myCallbackFunction()}}"></componentA>
</template>
<script>
    Polymer('componentB',{
   
    name: 'doug',
    myCallbackFunction: function(){
         alert("this works!");
         this.name='mike';
    }
});
</script>

So my problem is that I can pass myCallbackFunction in the attributes of componentA and it'll execute it, alerting "this works!". However, componentB name is still set to 'doug'. So I can successfully pass the function but how do I access component B's variables in that function?

Use events instead.

Component A:

<polymer-element name="componentA" extends="core-ajax">
<script>

Polymer('componentA',{
    requestCompleted: function(){
      // core-ajax already fires an event, but for demonstration
      this.fire('complete');
    }
});

Component B:

<polymer-element name="componentB">
<template>
    <componentA method="GET" on-complete="{{myCallbackFunction}}"></componentA>
</template>
<script>
    Polymer('componentB',{

    name: 'doug',
    myCallbackFunction: function(e){
         alert("this works!");
         this.name='mike';
    }
});
</script>