title: How to change the position of a Marker on a Android Map v2
body: <p>I need to do the following:
  I have a Marker on the map and I need to change the position of it. So I tried the following:</p>
  
  <pre><code>MarkerOptions a = new MarkerOptions()
              .position(new LatLng(50,6)));
          map.addMarker(a);
          a.position(new LatLng(50,5));
  </code></pre>
  
  <p>where map is a <code>GoogleMap</code>. I think I have to refresh the map or somthing equal?</p>