A power cut can leave the softener's display flashing or the clock wrong. That matters because many controllers run regeneration at a set time of day, and a wrong clock can start a cycle at a busy hour or skip one entirely. Resetting the clock is often a homeowner task. Other faults are not, and it helps to know where that line sits before you call anyone.
What you can reset yourself
Use the front buttons the manual describes to set the time of day. Check the regeneration time, and set it for a period when no one is likely to be drawing water, such as overnight. If the controller has a settings menu, confirm the hardness setting and regeneration type against the paperwork from the install. Write the settings on a card and keep it near the unit so the next outage does not start from scratch.
What to leave to a technician
Stop if the reset does not hold, if the display shows an error code the manual does not explain, or if the fix would mean opening the control housing, touching the valve, or working on the wiring or power supply. Those tasks involve parts that can be damaged or create a hazard, and they can affect warranty coverage. A technician should also check the unit if the water stays hard after the clock is right.
Confirm the settings after an outage
After any power loss, check the clock once, then watch the next regeneration. Confirm that the cycle ran, that the drain flowed normally, and that the water tests as expected at the tap. If the settings reset to factory defaults, use your written card rather than guessing. If the controller keeps losing its settings, ask the service provider whether a backup power feature or a different controller is needed, and get that answer in writing.