The Submitter (not co-presenter) can edit submission.  The Submitter (not co-presenter) can accept submission.

To Accept Submission

1. Log in to ABC and click My Options.
2. From the dropdown menu, click My Profile. 
3. Select My Options, then My Presentations (at bottom of list—lower right corner).
4. Click your desired submission.
5. Click Accept Approval or Decline Approval and follow the prompts.

To Edit Submission

1. Log in to ABC and click My Options.
2. From the dropdown menu, click My Profile. 
3. Select My Options, then My Presentations (at bottom of list—lower right corner).
4. Click your desired submission.
5. From the submission, find pencil icon on left.  After clicking the pencil, edit as desired. (Find co-author section by scrolling down past the long list of co-presenters.) 
6. GO TO BOTTOM & PRESS OK WHEN DONE.