What was found
CABIN EMERG LIGHT: DURING FLIGHT, WITH EMER LT SWITCH IN ARM POSITION, ALL EMER LIGHTS BEGAN FLASHING.///SIGN-OFF REMOVED AND REPLACE RH AFT EMERGENCY LIGHT BATTERY P/N 7450LS-00, S/N 005406. IAW EMBRAER PHENOM 300 AMM CH. 33-52-01-000-801-A. OPS CHECK GOOD.