I have used CkoFtp2 class for uploading files to server, can I easily make changes in code so that It can upload as sFTP?
The SFTP protocol is secure file transfer over SSH, and the semantics are very different than the FTP protocol. Both provide the ability for uploading and downloading files, but so does HTTP, and one wouldn't think to ask about easily converting code for FTP upload to HTTP.
Programs such as FileZilla provide a unified interface for FTP and SFTP, but remember, it is an application. Internal to the application, it is handling each protocol separately and very differently.
If Chilkat were to eventually provide an API that is a combination of FTP/SFTP, which may be a good idea -- but it would suffer from the typical drawbacks of providing a higher-level API -- which is that some flexibility and functionality would be lost.
Have suggested that in the past as combining the two into one would work so much better. It is a real pain to get to other folders, default is easy.
The answer is NO.