How can I alter Entity Auto Complete Results? I want to alter entity auto complete results in hook_form_alter.
My functionality is


  1) I have a entity reference of taxonomy and bundle is tags which is
  Level 2 (Field Name: Product Child) 
  
  2) In this I select one term from Level2
  
  3) I have another entity autocomplete which refers to taxonomy
  tags Level 1 (Field Name: Product Parent)


Now my question is if i select one Level 2 Term in Product Child Field , is there any option to show only parent terms of that Product child field in Product Parent Field
Like :

Cabbage (L1)
 -&gt; Fruit (L2)
 -&gt; Flower (L2)

Lemon(L1)
 -&gt; Lemon Fruit(L2)
 -&gt; Eatable (L2)


If I select Fruit in Product Child field I want to show only Lemon in Product Parent Field. Is there any way to do this.
I wrote a little module that shows how to alter entity autocomplete suggestions. You could try modify it to meet your needs. 
https://github.com/minnur/Alter-Entity-Autocomplete