A two unit redundant system is studied, in which one unit is operative and the other is at standby which replace the failure unit instantaneously. To increase system availability, the failure rate of the operative unit and the repair rate of the failed unit adjust automatically according to the standby unit. A two stage repair facility is available for the extent of failure, the repair facility by regular repairman and repair facility by expert repairman. The repair facility is prior with sending first failed unit to regular repairman and if damage is so serious then unit will be sent to expert repairman. Still the damage is not recovered then unit can be replaced with warm standby unit. Waiting facility is also available failure and replacement also. Using regenerative point technique in the markov renewal process, transition probabilities, mean sojourn time and mean time to system failure are obtained.