User Profile Edit workflow any module available, to implement a work flow when user is trying edit the user profile fileds (custom fields). Following is my use case 

1) User can edit the profile field , but admin approval is required to update it 
2) Admin can either approve or reject the profile update 
3) If it is approved need to change the user role , and need to send an email to the user 
4) If rejected , need to trigger an email again 

Thanks
There is need to work with Rules module make such action, "send email", "change role".

The workbench module is very popular, but is for Drupal 7 only. can be achieved good results using the revisioning module, which has a release for Drupal 6.