Another unit for rent in the building I have a condo

[Lorelai Gilmore]

This may be an unusual question. I rent a condo in the building and a similar unit is for rent through a property management company. I see it's not renting - i have a few nit picky ideas as to why but it's set for a great price in an amazing location. They posted their unit before I posted mine and I rented mine and theirs is still up for rent.

Did anybody get into the business of doing property management for others? I'm tempted to email the owners and offer up my services (would I need to have a business for this?) - I only currently rent one place. It would be really convenient since it's in the same building as my rental...