Retentive Timer Working

Sir in Retentive Delay Timer when one operation completes then accumulator and preset value becomes same and Done Bit is high. Then when we turn off the system Enable Bit becomes low or 0 but Done Bit will remain its high state or 1.
For this reason when next time we are going to operate this retentive delay timer then we have to toggle the Done Bit state to 0 and have to make accumulator value 0 manually.
In real time is it possible to change this state manually ?
In Industry how to make Retentive Delay Timer working automatically or we have to do this manually ?
Please explain this sir.