Is this possible?

The property I'm looking at is currently fully rented out (one unit is on NNN).
is it possible to qualify to put less than 20% down since the building proves there is income already? 

Or is it possible to get an assessment on the property and if it’s worth more than what I’m buying it for to pay the difference?

(Example property is selling for 500k. I get an appraiser to say it’s worth 550k. I pay the 50k difference for 20% of 500k). Does that work?

I obviously want to invest in this property but want to see if there’s other ways than having 20% cash on me of the properties value. 

Thanks all!