How to overwrite previously uploaded file with different extension.

Guys can any one help me for how to overwrite a file :

I have a fileupload on one interface from where i am uploading a file, and i have another interface from i want to upload the new version of the file.
I know how to overwrite the file if the same extension we are uploding by using the document id. Document is not getting overwrite, its creating new file in the selected folder. I dont want extension limit to upload.

E.g : on first interface i have upload .txt and when i am uploading final version of the same file i can upload any type of file e.g .txt, doc,xsd etc

OriginalPostID-249845