on second thought

on second thought

Having reconsidered or revised one's opinion of something. I'll take a tuna sandwich. Actually, on second thought, I'll have the soup.
See also: on, second, thought
Farlex Dictionary of Idioms.

on second thought

Fig. having given something more thought; having reconsidered something. On second thought, maybe you should sell your house and move into an apartment. On second thought, let's not go to a movie.
See also: on, second, thought
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

on second thought

Resulting from a revised opinion or change of mind, as in I thought I'd go to the movies, but on second thought I'd rather stay home. Similarly, have second thoughts means "change one's mind," as in I've had second thoughts about moving to Florida. This idiom alludes to ideas that come later. [Mid-1600s]
See also: on, second, thought
The American Heritage® Dictionary of Idioms by Christine Ammer.

on second thought

After reconsidering. This phrase, which often precedes announcing a change of opinion or decision, has been around for centuries. Many writers have proclaimed that second thoughts are superior to first; Euripides, Cicero, Sir Francis Bacon, and John Dryden all held that “Second thoughts are best.” Almost as many others have disagreed and maintained that second thoughts are markedly inferior, among them Lord Byron, Robert Fitzgerald, and the Earl of Shaftesbury (1711): “Men’s first thoughts are generally better than their second.”
See also: on, second, thought
The Dictionary of Clichés by Christine Ammer
See also:
  • on second thoughts
  • over the wall
  • as the white on rice
  • I'll see you (later)
  • I'll see you later
  • be a mixed blessing
  • get back to (someone)
  • I'll see ya (later)
  • in some neck of the woods
  • in this/that neck of the woods