Hi @Celia Geyer ,
According to my research, there is no built-in feature to turn off the default "Request Responses" in Outlook 365.
I submitted your feedback via the following link:
https://feedbackportal.microsoft.com/feedback/idea/da6eb246-d010-ee11-a81c-000d3a7a48db
Many features of our current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future.
You can mark my reply as an answer, so that other users in the forum who have similar problems can also vote.
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