When a job is completed only the admin or the original translator can edit that job.

You can change this behavior and provide access to other roles as well to edit the job.
Add the below code the functions.php

add_filter('wpml_user_can_translate', function ($user_can_translate, $user){
	if (in_array('editor', (array) $user->roles, true) && current_user_can('translate')) {
		return true;
	}
	
	return $user_can_translate;
}, 10, 2);