Button to close the poll

Hey all, how are you?

I'm trying to insert a close button on an advanced poll node that closes the poll without the need to edit the poll and select the option close poll.
I have already put the button and developed the action of the button that updates the field "advpoll_closed_value" to "close" on the table "field_data_advpoll_closed" but the poll remains opened.
Someone knows what more I have to do to close the poll correctly?

Thanks

Gustavo.