How to hide user-info block in "on behalf of" end user

How to hide user-info block in "on behalf of" end user

Hi,
I active "on behalf of" for end user that they can create a ticket instead of their colleagues.Now I want to hide the user-info block (attached) of their colleagues from the user who create the ticket in order to protect the privacy of the people. What should I do?

SDP v11.3.03
DB: MS SQL

Thanks for helping