On Thursday, July 20, 2017 at 4:23:29 PM UTC-4, micky wrote:
I have a "portable" AC with settings cool, dehumidify, and fan.

I understand "Fan" but what could the difference be between the other
two? How can it dehumidify without also cooling?

By returning the heated air to the room instead of pumping it outside?
That's how a dehumidifier works.