A lot of posts here will say that you can't which was the case when they were written. However Bravenet have quietly made changes to the service at some point in the not too distant past. I haven't tried or tested this myself but the instructions in the wiki say:
How to Modify Recipient
Login to your Bravenet user account.
Click on the Web Tools tab from the top of the page.
Click on the Email Forms icon.
Under the Email Forms Maintenance Options heading, click on Recipient Settings.
Select the form in question from the dropdown, and click Continue.
Type the desired recipient address into the field, and click Save.
You will be sent an authentication code by email, wait for it. When you receive it...
Input the authentication code emailed to you into the Auth Code field, and click Save.
If successful, that email form will now direct all form submissions to the indicated email address.
Looking at the instructions I would suggest temporarily turning off any spam filters on your email account to make sure that your authentication code doesn't get blocked by mistake.