Disposal of subsidiary-unrealised gain on PPE

Hi! I have a scenario whereby during the year ended 31 dec 2019, the parent disposed of a PPE to its subsidiary at a profit of let's say $1,000. As such, this unrealised gain has been canceled out during the y/e 2019. However, during 2020, the subsidiary has been fully disposed of. Grateful if someone could clarify me as the accounting entries iro the unrealised profit previously cancelled out in 2019. Thanks!