The Memory Repository will be imprinted every 5 Days. (Day 1, Day 6, Day 11, and so on.)
Unlike retrying a single Day, rewinding to the Memory Repository will maintain all unlocked Observations and gained E.G.O. However, department expansion and extracted Abnormalities will regress to the state of the imprinted Day.
You can elect to rewind to the Memory Repository in the ESC-Button Menu.