Approval of HR creating an expense report on behave of an employee

We need to implement an approval cycle for the expense report as follows:

here's what you have:

case#1:
IF :
an employee upload an expense report ( which is considers as the owner of the expense report )
where,
(Report creator = Report Owner = employee )
then
let the approval cycle goes in the normal flow
employee > line manager of that employee>> serial approval cycle

Case#2:
IF:
an HR upload an Expense Report on behave of an employee
then
the approval cycle goes as:
HR >> the line manager of the of employee(owner)>serial approval cycle
where,
(Report creator isn't Report Owner )(Report creator = HR , Report Owner= employee)