Display the selected field in a table

[Racso]

Hello,

When I select a manager like "AKIL Omar", I have his employees / collaborators.

In addition, "Akil Omar" has as manager "KERLERO DE ROSBO Christophe".

For the result, I want to have when I select a manager as "AKIL Omar", "Akil Omar" appears below cf. image as collaborator.

My idea: make a concatenation, I tried but it does not seem to work. Could you help me?