For our English speakers:
"I'm new in the configuration of WHD and I would like to assign a ticket to the tech lead or another tech if it is absent.
Thank you for your reply."
You could put the tech as "on vacation" then assign a backup tech. This makes any tickets that would go the on vacation person go to the backup automatically.
Thank You for Your answer but it didn't help me.
I may assign a lead tech to a given request type and "auto-assign" the ticket to this lead tech in my tech group. OK.
But when "auto-assign to lead tech" is enabled the ticket is sent to the lead tech regardless if (s)he is on vacation. There is no way to say "If lead tech is on vacation then send ticket to level techs or to a given tech in a given level".
That's my problem ! I can't set a property of the request type to redirect the ticket to another tech in case of the lead tech is on vacation.