Manually, using T-SQL :
1. On the primary server, execute sp_delete_log_shipping_primary_secondary to delete the information about the secondary database from the primary server.
@primary_database = N'AdventureWorks'
,@secondary_server = N'LogShippingServer'
,@secondary_database = N'LogShipAdventureWorks'
2. On the secondary server, execute sp_delete_log_shipping_secondary_database to delete the secondary database.
3. On the primary server, execute sp_delete_log_shipping_primary_database to delete information about the log shipping configuration from the primary server. This also deletes the backup job.