Is it possible to update records(locations) using spreadsheet loader

Summary: Hi Folks, I want to update some locations and am using spreadsheet loader to perform this action

Content (required): What I see is new records are getting generated and its not updating the current record. The supported action by default takes create and update when I create a spreadsheet template and I don't see if there is any way to only perform update and not create. In my case , its the code and the description that needs to be appended by a letter. But I think its creating a new location because I am guessing its checking for the code and if thats not available, its creating a new location. Is there a way I can