There are two ways to see it, in my view. If you were certain when you switched physicians that you had strong reasons for changing, I would cancel the appointment for July 18th and wait for the August 12th appointment, calling my current psychiatrist's office and asking for a transfer of my records to the new psychiatrist so that you will be up to date on everything on August 12th when you see the new psychiatrist.

If you are wavering in your thoughts about wanting a new psychiatrist after having
gone to the trouble of making arrangements for a new one, I'd cancel the appointment
on the 12th of August and go in the see my current psychiatrist on July 18th to
discuss the fact that you think a change would be helpful and get his feelings about
it. Let the new psychiatrist's office know that you will be seeing your current psychiatrist
for one more visit and if the change is called for you'll be back in touch.

Otherwise, I'd just keep the August 12th appointment and request that the current psychiatrist forward records to the new doctor. You need to keep stability in either choice of doctors, and
you need to do it so that you have records in the right place at the right time.

I wouldn't just drop one without having records transferred.

It also keeps the insurance current and stops questions regarding changes that might occur.