How do I delete an ongoing fiiling which hasnt been submitted and start over?

You don't have an ongoing filing if it has not been filed. If you really want to start over, just delete the file when you first enter the app where the file to use is selected. Of course, all you have to do at that point is start a new file anyway and it will ask you for the same information again.

A better way is to modify what you have already entered until you get it corrected to you want it to be - rather than start over.

You can simply use the "clear and start over" feature in the program.  

 Here are the steps:

• Sign in to your account, select Pick up where you left off
• To your left, select Tools, click on the drop-down menu
• Select Clear and Start Over

@achu17