I looked everywhere I can think of (including the documentation) and couldn't find how to update the email address with which I initially signed up for a dashboard account.
This email address would be needed for lost password reset.
One can create an new contact ("Add Contact"), and even make that new contact an account owner, but it is not clear whether the email address of that contact could be used for password reset ... and the wording on the password reset page suggests that it couldn't be ("please make sure you've entered the address you registered with")
P.S. as a final try I thought I'd look in the API docs, and it does indeed seem as though /api/v1/account/update/ could conceivably do the job.
Does that mean I need to write and run a python program in order to update my email address?