There is a magnetic pole reversal, which has apparently happened several times in the past. It would severely disrupt our electronics and the radiation from the sun would have very bad effects on life. However, a pole flip is not the same as a change from the current 23 degree tilt to another angle. The earth bulges at the equator and is flat at the poles, so that would mean catastrophic shifts in the crust. I have also read it would result in winds exceeding a category 5 hurricane. Not much would survive something like that. That said, God can do anything He pleases, and I believe the verses in Isaiah and Revelation about the earth being reshaped. 