This is antithetical to how IMAP is design to work - **what is on the client is a representation of what is on the server**, not the other way around. And as far as I know there is no RFC standard to do what you are as asking for. But there are import tools you can use. I'm sure support people can tell of their experience with these.
Bug 1545883 Comment 1 Edit History
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This is antithetical to how IMAP is designed to work - **what is on the client is a representation of what is on the server**, not the other way around. And as far as I know there is no RFC standard to do what you are as asking for. But there are import tools you can use. I'm sure support people can tell of their experience with these.