How do I change drive on remote panel?

You are probably connecting with WinSCP to SSH server on Windows. SCP and SFTP protocols use Unix concept on one-directory-root. It collides with multiple roots (=drives) on Windows.

Each SCP/SFTP servers solves the problem in different way.

So far the only server that offers solution for graphical clients is Vandyke VShell. It implements SFTP protocol extensions that lists drives on the server. WinSCP is then able to show them on remote directory tree.

On other servers you usually need to use Open directory command and type path to another drive manually.

On OpenSSH server you need to type path like /cygdrive/X, where X is the drive letter. On Vandyke (and some others) server you need to type path like X:/, where X is the drive letter.

If you usually use one drive only with WinSCP, you would probably want to bookmark it, not to type it again all the time. Or use it as initial remote directory.