Don’t be fooled by the command name “move.” It copies files. After the command is executed, both the original file and the destination file will exist. If you want to delete the original, it must be deleted with the delete command.
Unfortunately, you don’t say if the pre-existing file must be kept or not.
If you want the file being moved to overwrite the existing file of the same name then
tell app "Finder" move file [path name] to folder [path name] with replacing end
If you want the existing file to be renamed (and thus kept) prior to the move, you’ll need to write the code that does the following (the following IS NOT applescript:
set flie list to names of files of destination folder set new file to name of file to be moved if new file IS NOT in file list then move new file to destination folder else rename, trash, or move old file end tell
It might suffice if you wish to retain all old files (with identical names) to create a new folder, then move them into that folder.