Registration start and end date for a given season can be set in the Setup->Organization->Season Manager. The page will list all the seasons available to the league you are currently in. Click the Edit button on the season you would like to edit.
For a given season, you may edit the registration start and end date, as well as the season start and end date.
Don't forget to click update to save your changes.Tags: registration, registration end, registration start, season, season editor, season end, season start