According to our test, only the owner of the Form can directly delete the Form on Update. Other users cannot directly delete the Form created by other users on Update.
The Form created in Update is essentially saved in the Dataverse table msmwt_reportdefinition.
As an administrator, you can go to the Dataverse table to delete the Form, but according to our test, even after deletion, the Form is still displayed on Update, and when you click it, it will show that the Form has been deleted.
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