You cannot get the child tax credit at all -- ever-- for a child who does not have a Social Security number. If your child has an ITIN then you may get the $500 credit for other dependents, which can lower the amount of tax you owe. That $500 credit is not refundable.
https://ttlc.intuit.com/turbotax-support/en-us/help-article/internal-revenue-service/get-individual-...
It is odd that you are asking how to remove the additional child tax credit. When you entered information in MY INFO, what did you enter when it asked you for your child's SSN or ITIN? If they do not have a SSN or ITIN, you should not even be entering anything about the child on your tax return. Did you "make up" a number and enter it and get the child tax credit?
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
