The dropalias option is used to drop an alias representing a database name.
sp_webservices 'dropalias' alias_name
alias_name
The alias to be dropped.
Drops the marketing_alias alias:
sp_webservices 'dropalias', marketing_alias
An alias cannot be dropped if it is being referenced by a deployed user-defined Web service. To drop the alias, you must first undeploy the user-defined Web service that references the alias.