If you truly are a REALTOR® you wouldn't be asking this question.

Hire another realtor to represent you.

How can you not know this if you are a Realtor? What would you do to help a client in this situation? Maybe you need representation by a more knowledgeable agent to help.

Mr. anonymous real estate agent, perhaps it is time to retake the pre-license classes in your state or province. Even the Utah students could answer this question

You should know by now how to contact property owners.

Not trying to be mean spirited but you need to consider another career.

This is Real Estate 101...if you don't know the answer to your question, your are not ready to buy properties for your personal use. You need to take some classes and talk with your broker before even considering such a venture.

Seriously?

Are you serious? 

You could start with the tax records and send a letter asking for an appointment. 

I'd try tax records, online searches like Spokeo.com, prder the property profile or knock on the door. Good luck! 

Every county has a land records office and a treasurers office, both will have the names and addresses you are looking for, most are even online.

Send a lender to start with and tell them you are interested in here house

I've done that in the past, when I was searching for a single family ranch style home....I mailed to all ranches in the town....two responded.... I bought one and listed the other!!!! that was 12 years ago, and I still own and rent out that home....

There are services you can buy that will get you phone numbers if you prefer to call.  I don't know speciically as I'm not a caller, but if you google, you will be able to decide from a list.  If you are truly interested in doing this, you might want to check out the biggerpockets website.  There is a lot of help there on how to find properties for sale.  And remember what Annette says, if you have a license, you have to disclose, disclose, disclose.  Also talk to your broker and ask him what the office policy is about purchasing for yourself and what fees are owed on the transaction.

I would mail letter first, and ask if they are interested in discussing selling their  property to you at some point. Include your email, and phone #.

Your local tax records should provide the information you need. Then, hire a buyer agent.

As other have pointed out, door knocking might get you somewhere. Not my style for a myriad of reasons, but it probably is the fastest route to get some answers.

Alternately, do some online or in-person research at the county records office and library. e.g. our county assessor's office's property record shows the name and mailing address of the property owners, who might or might not live in the property itself. Then a phone book search (try county library for a copy) usually will net the phone number. The county assessor's record also provides a whole lot of other goodies that will help you in evaluating the property and for structuring a reasonable offer should the owners actually be interested. 

Ultimately, the how of contacting them (knock, call, letter, other, some combination, etc) is up to you and what lies in your comfort or stretch zone.

If you come to a full awareness of this subject matter, then results will follow. Part of the wanting to know is the seeking out for yourself. Good start

Check tax records - mail letter

Knock, Knock

or Letter

Knock on their door.

I am not into door knocking, so I would send a letter expressing my interest and asking if they are willing to sell their property to give me a call.

Knock on the door.

Sure there will be the occasional curmudgeon on the other side, most likely real estate agents who can not bare up under such inconvenience.

Let me assure you, as a 'real estate agent' if you have not figured out the answer to the question you post, big red flags are going up. Something is not right.

Reaching the citizen is the EASY part, it is what you say next that is critical.

NOTICE: you are aware that as a real estate agent there are very specific things you MUST disclose that will not be beneficial to your plan.

I would not want anyone knocking on my door and asking if I want to sell.

Go old school. Knock on the door!

Door knock is the only certified way to meet the owners.