Providing you haven't filed yet (or you e-filed but got rejected), you can simply revisit the File section again to choose a different method of receiving your refund and change the information for your checking account (routing number).
However, if you have successfully e-filed and your return was transmitted to the IRS you are unable to make changes to your refund method unless you are for some reason rejected and needs to be refiled.
If your return is filed and not rejected, and the IRS unsuccessfully tries to deposit into your wife's account, they will send a check after a couple of attempts, to the address on your tax return. This may, however, delay your refund.