If you have the property under contract and have put down earnest money, you have what is known as "equitable interest" in the property and are free to market it and bring in inspectors, investors, contractors, your grandma...etc
Just be sure for your own purposes that you know what the deed restrictions are for the particular bank who owns the REO. Some won't allow you to resell for a certain amount of time after you own it, some will allow immediate resale but only for a certain amount above the amount paid for it. ie Fannie and Freddie won't allow you to resell for more than 120% of purchase price within 3 months. Some agencies won't allow you to resell AT ALL within 30 days or more. Just confirm. Your realtor should know these details if they list enough REOs.
It's easier if your realtor knows what you're trying to do and can help guide you, but it's not necessary in most cases. Many of not all REOs are vacant and at least in my market of Chicago, are on a lockbox with a code that you can request from your realtor. Most realtors are happy to give out this code rather than have to give you access to the property every time you need to see it.
Hope that helps!
