save mail attachment

I found a script to save a mail attachment and use this with a rule in Mail. How can I adjust the below script to overwrite an existing file?

using terms from application "Mail"
	
	on perform mail action with messages theMessages for rule theRule
		
		tell application "Mail"
			
			repeat with oneMessage in theMessages
				
				set {mail attachment:theAttachments} to oneMessage
				
				repeat with oneAttachment in mail attachments of oneMessage
					save oneAttachment in ("MacBookProHD:Dropbox:") & (name of oneAttachment
					
				end repeat
				
			end repeat
			
		end tell
		
	end perform mail action with messages
	
end using terms from

Thanks in advance