Offering withdrawal options to participants allows those who wish only to withdraw from future contact to authorise continuing use of previously collected materials; others may withdraw fully.
It emerges after a pause, only to withdraw again if the tap is repeated.
We've got to begin not only to withdraw our troops, but bring that money back home.
It would be shameful to deploy more troops only to withdraw them later.
Israeli forces have repeatedly seized Palestinian areas of the city, only to withdraw eventually, to the settlers' consternation.
One of his Philadelphia friends, Ben McLaughlin, had also made the World Cup team, only to withdraw.
Houston was booked to sing in the medley at Sunday night's Academy Awards only to withdraw after the initial rehearsals.
But it then confirmed they had places in another hall, causing them to cancel their temporary accommodation - only to withdraw the offer because there wasn't enough room.
Mr. Ho has flip-flopped several times since then, initiating legal action to reclaim control, only to withdraw it shortly afterward.
British forces often fought their way into insurgent areas, only to withdraw and let the Taliban return, exposing residents to retribution.
All are notable figures who were invited to participate in college graduations in recent years, only to withdraw or be disinvited in the face of campus protests.
