Here are the filing instructions from the California Franchise Tax Board: " Form FTB 3840 must be filed for the taxable year of the exchange and for
each subsequent taxable year, generally until the California source deferred
gain or loss is recognized. Attach form FTB 3840 to the California tax return,
or file separately as a California information return if the taxpayer does not
otherwise have a California filing requirement."
Since you have no changes to your actual return, I do not suggest amending. Instead, I suggest signing and mailing the form to the address shown in the instructions with a copy of the original tax return. Write on the top of the form "Duplicate Filing to Attach Form 3840" or language to that effect on the top of the first page.
It does appear that the information on the annual return will not change until the new property is sold or transferred.
