Patio is unlevel. Water stands within the middle. How do I height this out? Patio was poured and not leveled for adequate drain rotten. Water...

Patio was poured and not leveled for adequate drain rotten. Water stands in the middle. How can I fix this problem?
Not much you can do. Other then pour a new slab. rip it out .Start again. Only road . Self levelling conc is fine but it will not stay fine . It will not stick to old concrete.
You can have someone "pump jack" the slab so it have some fall to the outside. Prior to this you will want to have them sawcut the slab so as they incline it - the slab cracks along those sawcut lines.
The slab will crack if you raise it up - even just somewhat - however controlling where it cracks can be done with a sawcut using a concrete saw next to a diamond blade.
That is what I would do short of busting it out and removing it.
Answers:    Best and easiest way would be to acquire self leveling concrete. They sell this stuff probably at your local hardware store. Just pour it where the un-level subdivision is and it will automaticly level itself out with the exsisting quad. It may be a different colour though so you may want to paint the patio afterwards. If it is patio stones next just remove the stones where the unlevel bit is and add some stone dust to even it out.
Sounds approaching it is time to build a new bigger better patio near a hot tub and gazebo