Hi, I would like to update a field value when a user clicks on a link or button on a email sent out by salesforce. 

We have a workflow that sends out automatic reminders about certain jobs. I would like to setup a second workflow that sends an email 2 days later with a button or link (e.g. "Job completed? Yes, No?") for the user to click on. That button or link should then update a field value in salesforce to "Job completed" or "Job cannot be completed". It doesn't matter if it's a picklist or text field, - I just can't figure out a way to update a field by clicking on a button/link in an email. 

I greatly appreciate any help. 

Alex