On occasion you may need to remove the S4B Mac client. Thanks to both Kam Foo Aw and Yong Lim we now have a very easy way to do so. All credit goes to them. I am just sharing the knowledge. As with all scripts use at your own discretion.
You will need to save this as a .sh file and run it with root permissions.
# SFBMac uninstall script v. 1.1
#!/bin/sh -e
sudo rm -rf /Applications/Skype for Business.app
sudo rm -rf /Library/Internet Plug-Ins/MeetingJoinPlugin.plugin
defaults delete com.microsoft.SkypeForBusiness || true
rm -rf ~/Library/Containers/com.microsoft.SkypeForBusiness
rm -rf ~/Library/Logs/DiagnosticReports/Skype for Business_*
rm -rf ~/Library/Saved Application State/com.microsoft.SkypeForBusiness.savedState
rm -rf ~/Library/Preferences/com.microsoft.SkypeForBusiness.plist
rm -rf ~/Library/Application Support/CrashReporter/Skype for Business_*
rm -rf ~/Library/Application Support/com.apple.sharedfilelist/com.apple.LSSharedFileList.ApplicationRecentDocuments/com.microsoft.skypeforbusiness*
rm -rf ~/Library/Cookies/com.microsoft.SkypeForBusiness*
sudo rm -rf /private/var/db/receipts/com.microsoft.SkypeForBusiness*
rmdir ~/Library/Application Scripts/com.microsoft.SkypeForBusiness
find -f /private/var/db/BootCaches/* -name "app.com.microsoft.SkypeForBusiness*" -exec sudo rm -rf {} +
while security delete-generic-password -l 'Skype for Business' ~/Library/Keychains/login.keychain; do :; done
killall cfprefsd