No, Verizon doesn't have towers in Ghana, and the frequencies used for cellphones (and the small amount of power they transmit) won't go far enough to reach a tower in the US. You can check the local carriers in Ghana to see if any of them have arrangements with Verizon to allow Verizon customers to roam on their towers. (But a local SIM would probably be much cheaper - Verizon is about the most expensive wireless carrier there is.)