Follow the below steps for editing registration start/end dates from the event manager.
Please note: you must edit each ticket separately and then save the changes at the very bottom of the registration page to finalize these changes.
Step 1: Click the 'Manage' link just above the event posting, or from the 'Post & Manage' section, to edit your event:

Step 2: Click 'Edit Registration' from the event manager page:

Step 3: Edit registration start/end dates for each specific ticket and save final changes at the bottom right hand corner of the event registration page:
