Thank you everyone for your replies.

I wanted to extend the rental by 4 hours, meaning return it 4 hours later and don't mind paying the daily charge. The problem is my rate right now is $152 for a 2 day rental. When I try to extend the rental, the total charge changes to $376. I tried calling the Hertz number but it said that it is after business hours and to call tomorrow by which time it will be too late.

My rental contract has not started yet, but I wanted to know if I can expect to pay $200 plus to extend my rental for a few hours once my contract does start, which is greater than the cost of a 2 day rental?