There are quite a few issues that are “resolved” by deleting the account and creating it again.
For that it would be practical to have an export/import function for the account data; neither the URL nor the password are typed that easily via a smartphone on-screen keyboard.
Furthermore, this could be used to easily copy account information between phones that should share a common calendar.
If the export format is plain text (perhaps with the password base64 encoded), doing trivial modifications like changing eg. the username could be done in the intermediate file.