Change livereload default port

I need to use livereload on 2 projects simultaneously. However, it uses a default port and once the port is used by one project’s livereload, the other project cannot use livereload.

Is there a setting to change the default port used by livereload? I tried 'reload_port: ’ in my config file but it didn’t have any effect.

bundle exec jekyll serve --livereload --livereload_port 8888