If you want to recreate the database (for testing in this case), you can use repair instead:
“C:\Program Files\Duplicati 2\Duplicati.CommandLine.exe” repair
“azure://azureContainer?azure-account-name=azureAccount&azure-access-key=myAccessKey”
--passphrase=“MyPassPhrase”
--dbpath=“C:\ProgramData\Duplicati\MyPCName-rebuilt.sqlite”
Since MyPCName-rebuilt.sqlite does not exist, it will create it.
If the database exists, it will instead try to repair the remote storage.
Not sure where you got --rebuild-missing-database from, it is not listed as a supported option?