1.16 Rogue Time (The Flash 2014)

Plot Summary
As Barry finds himself in the past (a day earlier), he starts to repeat things which alerts Dr. Wells to speak with Barry privately as he notices Barry had time traveled. He tells Barry to do the exact same things. However, Barry captures Mark. Dr. Wells reprimanded Barry and warns him that averting another tragedy will bring something worse.

Due to Barry's actions, Cisco instead visits the birthday party of his brother compared to what he did in the past, make a device to neutralize Mark's powers. Snart and his group capture Cisco and his brother and forces Cisco to make guns for him, his sister, and Mick. When Cisco's brother attempts to break them out, Snart attacks Cisco's brother and threatens to freeze him in exchange Cisco tells Snart about Flash's secret identity.

With Snart learning Flash's identity, Barry confronts Snart and makes a deal. In exchange for not taking any lives or hurting his family and friends, Snart agrees to Flash's conditions and not release Flash's identity. Barry lets Snart go.