Your title remains private and will not appear in the NetGalley catalog until you change its availability status. To add the title to the catalog, look under Availability section on the left-hand side of the Title Details screen and click the orange arrow.
Read more about the options for allowing requests here.
Private titles can still be viewed by members if they have a direct link, or you invite them via a NetGalley widget. You can always make a title private again at any point if you wish.
NetGalley clients are not obligated to place any of their titles in the NetGalley catalog for member request; title availability settings are entirely at the discretion of the client.