There are a lot of issues with these little words. Just a quick refresher on the general differences!
There: a place or location as in "She is standing over there"or "Yes, we will meet there"
Their: generally indicating possession Examples: "their coffee" or "their house"
They're: contraction for they are as in "They're going to the game."
Reign: to hold a royal office or hold influence/power over
Rein: to stop or slow down