How long until an amended return is recognized by IRS

[Snowman1962]

I filed my son's taxes for him and when I tried to file my own I received a rejection notice from the IRS. I discovered I had neglected to check the box on his return saying someone else could and will claim him. I did amend his taxes and the amended return was accepted. I tried filing mine again and I get an error saying I'm using a duplicate Social Security number, which is my sons. I thought since I amended his return I would then be able to file mine but that doesn't appear to be the case. What should I do? 

[Bsch4477]

You have to mail your return. Amended returns can take 6 months or more to process. 

[fanfare]

this error means you must file on paper at the Post Office.

even after the amendment is processed, you will still not be able to e-File.

If you are expecting a refund, it is a costly mistake.