Upstairs
If by chance you meet a Lower Servant, you should walk past, leaving them un-noticed... you will spare them the shame of explaining their presence more...
Downstairs
Lower Servants: if you meet one of your betters in the house, endeavour to make yourself invisible 'give room', turn your back, and avert your eyes more...
"I really don't have problem with having servants...if I'm not being served, they don't have a job. This is absolutely magnificent. I'm enjoying it." Sir John Olliff-Cooper