Stand By Meaning

(intransitive) to be ready to provide assistance if required.

Example:   Please stand by for more instructions.‎
1935, George Goodchild, chapter 3, Death on the Centre Court:
  It had been his intention to go to Wimbledon, but as he himself said: “Why be blooming well frizzled when you can hear all the results over the wireless. […] You stand by, Janet, and wake me up if they do any of that running commentary stuff.”
  Even though money is scarce sometimes, Ann stands by her decision to be a full-time mother.‎
2014 August 20, “Why Jews are worried [print version: International New York Times, 22 August 2014, p. 8]”[1], The New York Times:
  [W]hen a Hamas spokesman recently stood by his statement that Jews used the blood of non-Jewish children for their matzos â€“ one of the oldest anti-Semitic canards around â€“ European elites were largely silent.
  They stood by us all along and it's awesome to see them out here to support us today.
  I can't simply stand by and watch you ruin your life.‎
  The tug stood by in case it was needed.