Time Reset is unique Mimic ability that lets them to turn back time in order to continuously retry different battle strategies until the they achieve victory. In Mimics, only Omega and Alpha has this ability with Omega inducing this state when it sees fit.
Humans can gain this ability when they come into contact with Alpha's or Omega's blood. This seems to be the only way to gain this ability. Infected humans can't transfer this ability to another human, whatever through blood transfusion or even sexual intercourse. Once the infected blood leaves human system by any means whatever through blood transfusion or bleeding out, the infected loses this ability permanently. Infected humans do not feature any physical or biological difference from ordinary humans besides on rare occasions having completely black eyes (this is seen twice when Cage is infected, stabs his leg with a Transponder and when he loses his blood trough blood transfusion).
Once infected with Alpha's blood, Omega begins to see that infected as an Alpha, thus it triggers Time Reset ability when it feels that said person has died.
While having this ability every time the infected human dies, he would travel back into the past day. The exact amount of how far the infected can travel into the past is determined by the Omega.