[DUPLICATE] My oldest filed his return and claimed an exemption for himself. Can I still get credit for him as a dependent?

[Zbucklyo · Accepted solution]

You can't efile and claim him as a dependent.  If he truly is your dependent, you can claim him as such and mail your return.  In the meantime, he would have to amend his return and indicate that he can be claimed as a dependent by another person.  The amended return would also have to be mailed.