Time Machine: How can you confirm a backup? Can you just delete the backup and it will automatically redo it?
The first question, how can you be sure a backup has completed, is answered by checking the menubar Time Machine item. It will tell you the date of the last completed backup.

Secondly if you want to perform another complete Time Machine backup you can stop Time Machine, eject the Time Machine drive, plug in a fresh drive and re-enable Time Machine using that drive as the backup destination. A complete new backup will be performed.

You could also just delete everything on the original Time Machine drive but it is slightly more risky. If something bad happened before the new backup completed you would be without the backup you are not sure about and the new backup.