Hi Gina,
From what I check, to be able to decline meeting without notification or response sent to the organizer of the meeting depends on what email platform you are using.
If you using Outlook.com web version, there is no option to not send responses when declining the meeting, so when you click Decline, it will automatically send a response to the meeting organizer.
However, if you are using Outlook app, there is an option for you to not send responses when you opt to Decline the meeting.