If you’re job hunting, it helps to have a few reliable references who can attest to your work ethic and professionalism. Ideally, a former boss or supervisor will serve as a reference, but you can ask former colleagues to act in this capacity as well. Select people you worked with on team initiatives who can testify to your reliability, dedication and productivity.

Make Contact by Phone

If your colleague is someone you’ve kept in contact with since parting ways, pick up the phone and give him a call. Make pleasant chitchat and inquire about his professional endeavors, and then get to the point of your call. “Listen, John, it has been great to catch up with you. One of the reasons I'm calling is to see if I can use you as a reference for a job I'm applying for. I’m in line to be the next communications director for ABC Company, and they’d like to talk to someone familiar with my branding strategies. Is that something you'd be comfortable with?”

Make Contact by Email

If you haven't spoken with your colleague for a while, calling him out of the blue can put him on the spot and create an awkward scenario if he's not comfortable giving you a reference. Instead, write an email outlining your request. “Hi John -- I'm applying for a job as a communications director for an advertising firm, and I'd love to use you as a reference. The company is built on branding, and if you could talk about the shopping center branding campaign we worked on several years ago, that would be great.”

Be Specific

Be specific in what you're asking your former colleague to do for you. If you want to list his name and contact number as a reference a potential employer can call, he has to be open to discussing your professional work history. Questions may range from your reliability to how you problem-solve, and your colleague should be comfortable endorsing you from a number of perspectives. If you're asking the colleague to write a reference letter on your behalf, be specific about the job you're applying for, what you want the reference to cover and when you need it.

Don't Take It Personally

For various valid reasons, a former colleague might not want to serve as a reference for you. Maybe he’s uncomfortable vouching for someone who was a colleague and not someone he supervised. Perhaps he had some issues with your performance he never discussed with you because you were coworkers. If you're in the same industry, he may be interested in the job himself or be supporting someone else for the role. Regardless, if a potential reference is uncomfortable with taking on the task, let him off the hook to maintain a professional and cordial relationship.