Simple workflow script

I need a simple Workflow 3 or 4 levels of steps in php. A person sends a request about 6 fields. It goes to the first employee for verification , he can reject the request or send it to the next employee after adding comments on 3 fields. It goes to the second employee who approves or deny the request, an email should be sent to the person who sent the request and another mail to the first employee if there request gets approved.