The first major step to getting a job back after quitting is to leave on good terms and avoid burning bridges on the way out the door. By doing so, a person may have a shot at returning to the job by maintaining contact with former colleagues and managers.
Leaving gracefully, giving proper notice and thanking the manager before moving on increases the odds of the door being open for a return. Staying in contact with colleagues via email and social media allows a person to stay in touch with what the organization is doing. Also, close colleagues may offer insight as to the mood of the work team and manager, along with insights on the right time to inquire about the position.
After taking time to ensure a return is the best option, call the manager and request a meeting. The former employee may have to pre-sell the manager on the point of the interview. If granted, the job seeker is likely to hear many questions about his reason for leaving and for wanting to return. The manager wants to know that the employee is going to recommit to the position. Giving honest answers and valid reasons for the departure and return is the best approach.