You can amend your return, or you can wait for the IRS to realize that what you filed doesn't match their records. They will propose an adjustment to your return and notify you by mail. If you wait for the IRS and you owe additional tax, the meter is running on interest and penalties. So I would file an amended return. For information on how to amend your 2017 return, see the following FAQ:
https://ttlc.intuit.com/replies/6603004
