The 2399 transfer of Jean-Luc Picard's mind into a synthetic body after he died on Coppelius, during which he said a final farewell to Data.
After the Coppelius standoff Jean-Luc Picard died from a long-diagnosed brain abnormality. Altan Inigo Soong and Agnes Jurati transferred his mind into a synthetic body, or golem, built to resemble him closely and to live out about a natural human lifespan.
While his mind was between bodies, Picard met Data's consciousness, which had been stored in a quantum simulation. Data asked to be allowed to die, and once Picard awoke in his new body he honored that wish, ending the simulation.