If Siri doesnt hear what you say exactly there few ways to correct it.

• From the Siri Screen, tap the bubble of what Siri heard you say. You can now edit your own words by typing or tapping the microphone icon to dictate.
• Correct words underlined in blue, you can change it by tapping on it, type it the correction or dictate by tapping the mic icon.
• Correct Siri by voice, Restate and clarify your request. Tap on Siri again and retry.
• Correct a mail or text message, if you want to do some corrections before a message is sent out you can say things like,
  • No This keeps the message without sending it.
  • No, send it to Billy.
  • Cancel.
  • Change it to, See you next week.
  • Add, Do we need eggs question mark.