References come into play when a job offer seems close. However, your chances grow iffier if you must acknowledge leaving your last employer on bad terms. Even so, you can immunize yourself against an unflattering reference. Your career hangs in the balance, so you'll need to call on your employer and ask him to reconsider his negative stance. If an understanding isn't possible, you must carefully consider how you'll address the issue during your interview.

Contact Your Ex-Boss

Calling an ex-boss who you feel won't say positive things feels intimidating, but you have nothing to lose by trying, as "U.S. News & World" career columnist Alison Green states. Acknowledge the rocky parts of your tenure, and share what you learned from them. Find areas of agreement, and ask if your former employer is willing to stress them in future reference calls, Green suggests. The worst that can happen is that you'll get turned down.

Contact Your Other References

While you're at it, contact other references that aren't related to your last position -- preferably before you start looking for a new job, the Net-Temps website suggests. However, if you wait until the actual search, ask what former bosses or co-workers are willing to say about your abilities. You don't want lukewarm or overly candid comments from others to complicate an unflattering testimonial from your last employer.

Confront Illegal Or Malicious Comments

Employers who make illegal or malicious comments during reference checks pose a different problem, but you must confront it. For example, your ex-boss might falsely claim that illegal acts -- such as theft -- prompted your departure. Comments that suggest defamation, discrimination, retaliation or sexual harassment are also illegal, hispanicbusiness.com states. In response, Green recommends going to your former employer's human resources department, or politely reminding him that he's risking a potential defamation claim. You can underscore the point by sending a cease-and-desist letter through an attorney.

Defuse the Situation

If you can't reach an understanding with your last employer, you'll need to defuse the situation during the interview. Unless you give them reasons to probe further, most hiring managers care more about how you'll fare in a new job, according to the Net-Temps website. Admit the problems, but stress that they're not relevant anymore, and refrain from going into detail. Don't try to explain, or make excuses, which only digs the hole deeper.

Other Considerations

Your interview depends on how you frame your responses. If you left on bad terms, you can acknowledge the situation without implicating yourself in any way, according to interview preparation materials posted by Douglas College. For example, you can indicate that your job description changed, you wanted to rethink your career, or just didn't see eye-to-eye with corporate practices. A carefully considered response will prevent you from trashing your former employer, which is a deal breaker during any interview.