REO properties have already been to auction. Once the bank forecloses on a property and has an auction then it becomes an REO (Real Estate Owned). Finding the auction date at this point therefore would require looking back in time. If you're interested in putting in an offer on it, then you'll want to find the REO broker that the bank plans to use. I'd go to the public records find out who the lender is, call them and ask. They may not give you any info if you're not authorized, but they may! Also, the lender's often advertise REO's on their websites before they hit the MLS. You may need to dig a little.
If you have or able to get the lender's information you should contact them directly. However, usually addresses and auction dates are published weekly in the local newspaper. I hope this helps! If you have any other questions feel free to email me directly at email@example.com. Also if you need me to obtain the local paper for you and send it to you - let me know I have a home in Maine that will be at next week.
Licensed Massachusetts REALTOR