display employes who report to the user id given if user id given is team lead , else display the employes who report to the given user id's team lead

declare @teamLead as int
declare @eid int

select @eid = 4

select @teamLead=TM_UserID from TM_USER where Report_To=@eid

if @teamLead is null
begin
    select @teamLead=Report_To from TM_USER where TM_UserID=@eid
end
else
begin
    select @teamLead=@eid
end


(select distinct emp.TM_UserID,emp.FullName,TL.FullName as TeamLead from TM_User EMP
join TM_User TL on emp.Report_To=tl.TM_UserID where ( emp.Report_To=@teamLead  ))