Does anyone know how can I reset the username and password for CouchDB ?
One more point to add ...
If you are running Couch DB on Windows, then probably it was installed as a service and to reset it you need to stop service first, within running service other answers do not work.
http://www.7tutorials.com/what-are-windows-services-what-they-do-how-manage-them
Open Control Panel - Administrative Tools - Services and stop Apache Couch DB