There’s no standard way to duplicate a remote file over the FTP protocol. Some FTP servers support proprietary or non-standard extensions for this though.
Some FTP clients do support the remote file duplication. Either using the extensions or via a temporary local copy of the remote file.
For example WinSCP FTP client does support the duplication using both drag&drop and menu/keyboard command:
- It supports the
SITE CPFR/CPTOFTP extension (supported for example by the ProFTPDmod_copymodule) - It falls back to an automatic duplication via a local temporary copy, if the above extension is not available.
(I’m the author of WinSCP)
Another workaround is to open a second connection to the FTP server and make the server upload the file to itself by piping a passive mode data connection to an active mode data connection. This solution is shown in the answer by @SaadAchemlal. This is basically use of FXP protocol, but for one server. Though many FTP servers will reject this, as they wont allow data connection to/from an address different to the client’s.
Side note: people often confuse move with copy. In case you actually want to move, then that’s a completely different question. Moving file on FTP is widely supported.