In the following let Archive=/usr/local/src, or a similar path that refers to the location of the slisp sharable archive. Let Local=$HOME/src, or a similar path that refers to your personal copy of slisp in your home directory.
To merge your changes back into Archive/slisp Scopy can be used in the reverse direction. That is, cd to your local copy of the application directory you are working with (e.g. Local/slisp/sl), and run Scopy Archive, which will replace the archive copies with your files of the same name, leaving other archive files unchanged. This assumes you have write priviledges in Archive.
Before you do this please add a description of your changes to the front of Local/slisp/Changelog.txt, which will then replace the version in Archive. It is also important to not upload your changes before you have donwloaded someone else's changes or you will overwrite them. Since we are not yet using a revision control system we need to communicate often with each other.