I will write generic HR practice instead of filtering the knowledge for Cognizant.Whenever an employee leaves the organisation, HR marks the employee profile (after inputs of Manager) if he/she is re-hireable or not. So you may find employees who leave the organisation after a feud or in worst case getting sacked do not receive alumni mailers or re-joining requests. That is because they are marked as u201cNot re-hireableu201d (nomenclature differs organisation to organisation).Now if someone has been asked to leave on disciplinary grounds then the employee is already tagged as u201cNot re-hireableu201d. If you are able to apply and interview is scheduled/cleared then rest assured, your candidate profile is still not uploaded in the HRMS yet. To release an offer letter, the last toll gate is profile creation in HRMS (remember those mailers from taleo to upload documents), and once profile is created, the HRD will get to know that the candidate has hiring restrictions and the process will cease to proceed.If the HR process is not robust and doesn't have such checks, one may get rehired. Or else if the employee was not tagged as u201cNot re-hireableu201d during exit then chances are there.