I suppose it depends on your agreement with your developer, as to whether more access is part of the deal. Perhaps you could ask to have a new user created, if you promise not to use it much?
If you can log in to the host control panel, however, you can use phpMyAdmin to manipulate the database. (If you can install plugins, you can install a plugin to do this also, or User Role Editor but I think it won’t let non-admin change much.)
You could
- simply change the admin’s email address to one you can access (it has to be different from any used already) and then go through the normal process of resetting the password for that user.
- duplicate the existing admin user, and change the details. This is more difficult because there is an entry in the meta table that has to match and gives the capabilities.
- try to change the meta entry for your own user to make it admin, by copying what the existing admin user has (but it has to match your user).
