Albert Barnes Commentary 1 Kings 12:7

"And they spake unto him, saying, If thou wilt be a servant unto this people this day, and wilt serve them, and answer them, and speak good words to them, then they will be thy servants for ever." — 1 Kings 12:7 (ASV)

The advice was not that the king should permanently resign the office of ruler, but that he should, for this one occasion, be ruled by his people.