Edit existing drop down list

Hi!! 

I am needing some drop down list help.. I have to edit an existing fillable form. I have the form pulled up for EDIT PDF but I can not figure out how to edit the already created drop down and it is driving me crazy. I even thought I could remove the drop down and recreate but I couldnt select and delete either. 

Example - 

Loan Originator: Choose One (drop down has names you can choose form) I need to remove old names and add new ones.... 

Thanks!