Hi @lnarayana ,
Using Graph REST APIs it is possible only to Create a new root message in a channel, Reply to an existing chat message in a channel.
You cannot edit/update a posted message in teams channel using Graph REST APIs.
Currently the policyViolation property of a chatMessage can be updated.
Note: This API has licensing and payment requirements. It supports the model=A query parameter. If no model is specified, evaluation mode will be used.
Reference: chat message methods
chatmessage-update
Hope this helps.
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