No. The code would have to change.
The easiest is probably Authorize.net. If you need a new merchant account you can try:
https://www.e-onlinedata.com/cafecommerce
If you don't want to redo the page, you can probably just apply the process payment server behavior for authorize.net and remove the paypal payment server behavior on your existing page. Or you could re-run the checkout wizard with new page names and just copy and paste to swap out the payment processing portion.