How do I amend my 2020 return through TurboTax?

Your son can only be claimed on one tax return each year; both of you cannot claim him.   The custodial parent is the parent that should claim the child.   The custodial parent is the parent whom the child spent the most nights with.  

 

Your ex would need to file an amendment to remove your son from his return in order for you to claim him on your tax return.   See the 2nd qualifier below.   

 

Qualifying child - the following must be true to claim a child dependent

• They're related to you.
• They aren't claimed as a dependent by someone else.
• They're a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They aren’t filing a joint return with their spouse.
• They're under the age of 19 (or 24 for full-time students).
  • No age limit for permanently and totally disabled children.
• They lived with you for more than half the year (exceptions apply).
• They didn't provide more than half of their own support for the year.

 

IRS reference - If the child meets the rules to be a qualifying child of more than one person, only one person can actually treat the child as a qualifying child. See Qualifying Child of More Than One Person, later, to find out which person is the person entitled to claim the child as a qualifying child.

 

 

Here are the full instructions on how to amend a 2020 tax return in TurboTax.