DropJob

CREATE PROC dbo.DropJob
@JobName AS VARCHAR(200) = NULL 
AS 
DECLARE @msg AS VARCHAR(500);

IF @JobName IS NULL
BEGIN 
SET @msg = N'A job name must be supplied for parameter @JobName.';
RAISERROR(@msg,16,1);
RETURN;
END
IF EXISTS (
SELECT subplan_id FROM msdb.dbo.sysmaintplan_log WHERE subplan_id IN
( SELECT subplan_id FROM msdb.dbo.sysmaintplan_subplans WHERE job_id IN 
(SELECT job_id FROM msdb.dbo.sysjobs_view WHERE name = @JobName)))
BEGIN
DELETE FROM msdb.dbo.sysmaintplan_log WHERE subplan_id IN
( SELECT subplan_id FROM msdb.dbo.sysmaintplan_subplans WHERE job_id IN 
(SELECT job_id FROM msdb.dbo.sysjobs_view WHERE name = @JobName));

DELETE FROM msdb.dbo.sysmaintplan_subplans WHERE job_id IN
(SELECT job_id FROM msdb.dbo.sysjobs_view WHERE name = @JobName);

EXEC msdb.dbo.sp_delete_job @job_name=@JobName, @delete_unused_schedule=1;
END
ELSE IF EXISTS (
SELECT subplan_id FROM msdb.dbo.sysmaintplan_subplans WHERE job_id IN 
(SELECT job_id FROM msdb.dbo.sysjobs_view WHERE name = @JobName))
BEGIN 
DELETE FROM msdb.dbo.sysmaintplan_subplans WHERE job_id IN 
(SELECT job_id FROM msdb.dbo.sysjobs_view WHERE name = @JobName);

EXEC msdb.dbo.sp_delete_job @job_name=@JobName, @delete_unused_schedule=1;
END
ELSE
BEGIN 
EXEC msdb.dbo.sp_delete_job @job_name=@JobName, @delete_unused_schedule=1; 
END 
GO

Now you can call the SP with the following;

USE [msdb];
EXEC dbo.DropJob @JobName = N'Shrink_AWP_Databases.Subplan_1';