At McKinsey, the minimum time between two attempts to go through the recruitment process is 24 months. The procedure is the same as on campus, with similar case-type interviews. There are two options for applying: directly through the website or through a referral. In either case, your CV will not be accepted until you have completed two years of work. The process for lateral hires is carried out 1-2 times per year, depending on the availability of roles. If your CV is chosen for further consideration, you will be contacted for an interview. If the partners interviewing you are unsure about something, the opinions of your batch mates will only serve as a push in either direction. Also, if you were previously shortlisted for campus interviews, those who interviewed you will be asked for their perceptions.
As a result, it would be beneficial to receive feedback on why you did not pass the previous exam and whether you were able to make up the difference in the two years between. For example, if you lacked leadership experience, did your workplace provide you with opportunities to demonstrate it? Have you gained experience delivering analytics-heavy projects if your academics or problem-solving skills were a weak link? These are the topics on which you will be grilled the most.
Lateral hiring for those who were previously rejected is extremely rare, and even if you make it, you will start at the bottom, a couple of years junior to your batch mates.