How to alter Fields of Field Collection? I have a field collection in a custom Content Type.

I wanted to do form alter.

I'm unable to locate the fields of field collection in hook_form_alter(), do we have any other way ?
try to use 
$form['YOUR_field_collection']['und']['0']['sub_field']['und']['0']['value']
for ex : to add ['#autocomplete_path'] would :
$form['YOUR_field_collection']['und']['0']['sub_field']['und']['0']['value']'#autocomplete_path']=''