@sweetsuzyq His tax return will have to be amended to change his dependency. It will take the IRS 20 weeks or longer to process the amended tax return.
You will have to print and mail your tax return, keeping him as your dependent on the return. The IRS will process your tax return as received without regard to your son's return. You cannot e-file your tax return.
See this TurboTax support FAQ for how to print a return for mailing when using the online editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/printers-printing/print-mail-return-turb...
