How can i changing the permalink "job" ?

Welcome to our forum,
 
Yes, you can changes as following,
Replace the line 54 as following file job-board-manager/includes/class-post-types.php , change the text "offer" as you want.

Before: 

'rewrite' => true,

After:

'rewrite'  => array( 'slug' => 'offer' ),

 
Please see the screenshot.
http://i.imgur.com/66DBPYy.png
 
Let me know for more help.
 
Best Regards