Tires: Replace 1 tire?, michelin tires, brand tire

Question
We have a HONDA 2007 Odyssey EX-L Minivan that has the original Michelin tires on it.  I just noticed a "chunk" about the size of a dime in the sidewall of the front passenger side tire. The cord is showing slightly.
Should I replace only 1 tire?
Should I replace with a different brand tire?

Answer
Sherrie,

If cords are showing, the tire must be replaced.

It is best to have 4 tires of the exact same size / type / make / model / state of wear.  

Vehicles tend to pivot around an odd tire in emergency manuevers and the more different the odd tire is, the more dramatic the effect is.

Since you have to replace the tire anyway, I would suggest that someone look at the other tires and help you make a decision.