Log in to the vCenter Server that is hosting the SRM/VSRA -> Administration > System Configuration > vSphere Site Recovery Manager. > Protection tab > Select the protection plan that you want to delete > Click Delete > In confirmation box, select Force Delete checkbox > Click Delete
Keep a few things in mind that you cannot delete a protection plan that is currently in use, Also if you delete a protection plan, any virtual machines that are protected by the plan will be unprotected
Further after deleting the plan, you will need to recreate it if you want to restore the virtual machines that were protected by the plan.
