strike the colors

Verb

strike one's flag (third-person singular simple present strikes one's flag, present participle striking one's flag, simple past struck one's flag, past participle struck one's flag or (rare or archaic) stricken one's flag)

1. (especially) To take down one's national or other representative flag in order to indicate surrender.
   • At length, having lost her fore and main-top-masts, and her mizzen-mast having been shot away to the deck, . . . the English frigate was reduced to the last extremity. Captain Cardan ordered his signal quarter-master to strike the flag.1850, Herman Melville, chapter 74, in White Jacket
2. (broadly, idiomatic) To yield, give up, or surrender.
   • The point of this exercise wouldn't be to cause one side of the argument to see that the other is correct and strike their flag.2014, David Berreby, “What If We Start Talking About Race Like We Talk About Religion?”, in bigthink.com, retrieved 02 Jul 2015

   Synonyms:

   give in, strike the tent, throw in the sponge, throw in the towel, throw up the sponge, wave the white flag