Has two meanings
(مَن حضرتكم?)
Means: Who are you?
Or
(مِن حضرتكم)
Means: from you
...
Note (حضرتكم) mean (your) ((the conscience of the offeree)) in the Egyptian dialect

This correction however, is correct :

ﻭﺍﺳﺘﻘﺒﻠﺖ ﺧﺎﻟﺪﺍ ﺳﻜﺮﺗﻴﺮﻩ ﺍﻟﻤﻜﺘب The office secrtary welcomed Khalid

 what Bilal explained is correct:ﻣﻦ ﺣﻀﺮﺗﻜﻢ

 i read it mistakenly: من حضراتكم

which is wrong. Two different words and meanings. Sorry about that, ignore my correction post.

ﻭﺍﺳﺘﻘﺒﻠﺖ ﺧﺎﻟﺪﺍ ﺳﻜﺮﺗﻴﺮﻩ ﺍﻟﻤﻜﺘب The office secrtary welcomed Khalid.

ﻣﻦ ﺣﻀﺮﺗﻜﻢ? It's like saying  honored guest or guests who are present at a gathering or event.