Unfortunately, the IRS no longer will accept amended returns for new social security numbers if the social security numbers were issued after the due date of the original return.
If you, your spouse or dependent child did not have a Social Security Number or ITIN (Individual Taxpayer Identification Number) by the due date of the return (to include extensions), you cannot claim the Child Tax Credit, Additional Child Tax Credit or American Opportunity Credit on either your original or amended return. This is true even if you later get an ITIN or SSN.
