you can reject the unwanted tickets and case can be aborted . as per below comments deletion of the work item has adverse impact on auditing/reporting.

Thanks for Feedback - Deletion of the work item in the platform will impact auditing and reporting in a negative way and this feature can be abused if we simply allow end-users to delete these packets. What's your view on this?

and if you have a trainee in the team and then please use test mode functionality of the product. any items created in test mode is excluded in reporting automatically.

Please let me know if you need more details.

Kamal