I rented from HNL for about 46 days last summer and they had to split it into two contracts, and made me come back to sign, but they were super nice and let me switch out cars when I came back. So you still might have to go back and resign a new contract but you might be able to get a better car out of the deal. The manager of the location is fantastic!!! She's extremely nice and gives great food recommendations. I'll look for her card and try to post her contact info if i find it.
Enjoy HNL and if you like burgers, check out "Burgers on the Edge" and you've got to hit Leonard's for some Malasadas!