Hi @minniep ,
Could you please share a screenshot of the configuration of your flow?
Do you want the "reply to email" action of outlook connector or the "Post a reply to a message" action of Teams connector would send the message and as sent by others?
The send by person would always be the connection account for the created action, you could add the connection for the special person and choose the connection for the special person for the "reply to email" action of outlook connector or the "Post a reply to a message" action, and the message would show as post by the special person:

Best regards,
Alice
Community Support Team _ Alice Zhang
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