how to report a previous home sale never reported in prior year

[RichardS77]

I have a client that sold their primary residence in 2020 for a loss.  They sold another primary residence back in 2017 but the sale (gain)  was never reported on their 2017 return. Pro Series will not accept another 2020 home sale  worksheet with a prior year sale.   How do I report this transaction in lieu of filing an amendment for 2017?

Any suggestions are appreciated.

Thank you!

[TaxGuyBill]

Was there a TAXABLE gain for the 2017 home?  Or was all of the gain eligible for the $250,000/$500,000 exclusion?

If the entire gain was eligible to be excluded, there was no need to report the sale on the Federal return.

If there was a taxable gain, then 2017 should be amended to report that gain.

[qbteachmt]

"They sold another primary residence back in 2017"

Were these owned consecutively or concurrently? They cannot both be primary if they existed at the same time or overlapped.