export/import to close/open account

Hi there! Thanks for reaching out in the community. Once you delete your account you can't reopen that same account meaning those documents in the account would be lost. You could technically export your files as Visio files and that would allow you to re-import them back into Lucidchart if you are really wanting to close your account and then open a new one. But a better way to do what you are asking is to just cancel your subscription so you have a free account. This way all the files you created will stay saved in your Lucidchart account although you wouldn't be able to edit them until you re-upgrade to a paid account.