Renaming table system unavailable SQL Azure : I have to perform the exchange of two tables and it's making my system unavailable for 20 minutes(are many data).

My sample code:

    query = "DROP TABLE MY_TABLE; ";
    query += "EXEC sp_rename MY_TABLE_TEMP, MY_TABLE; ";
    query += "ALTER TABLE MY_TABLE ADD CONSTRAINT PK_MY_TABLE PRIMARY KEY CLUSTERED (ID ) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]";


I wonder if it's like not to leave as Unavailable.