You might want to allow submitters to edit their original submission past the deadline, for example to address reviewer comments or to allow them to upload presentation material.
How to activate this option
Go to Submission > Form > Settings.
Under Options, toggle on Submissions can be modified when accepted.
Accept submissions
Go to Submission > Submissions. Accept submissions to allow them to be editable. You'll need to have at least one presentation type.
See the decision section for more information.