The night before you leave, push the Regen button. That will cause Regen today to flash on the screen and that will cause a regeneration at 2:00 AM. The next day as you leave, turn off your water and unplug the softener.
When you come back, turn on the water and plug in the softener. Set the correct time of day. Then run cold water at all sinks for 30 seconds and flush all toilets and at one sink the hot for 30 seconds. That flushes all the two week old and stagnant water out of the plumbing and softener. Then push the Regen button, regen today will be flashing and it will do a regen at 2:00 AM OR better yet, hold the regen button in until the motor starts and let go. That will do a manual regen two hours from then. After those two hrs, don't use any water for the next 1 hr 15-30 minutes or until the softener is finished. After the regeneration you have fresh and soft water and you're back on your old schedule. Hopefully the vacation went as easy as leaving the softener home alone and coming home to it and the house.