You can do as follows to reply email with selected text only in Outlook with the Reply Selection utility of Kutools for Outlook.

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1. Double click to open the email that you will reply with selected text only.

2. In the Message window, please select the text you need to include in the reply message only, then click Kutools > Reply Selection. See screenshot:

Then the RE email window pops up, you can see the selected text of the original email is listing in the email body. Please compose your email and then send it.

Note: This feature will not be applied if you don’t select any text in the message.