Yes, Turbine supports two-stage approvals.
This means that you can configure the system so that all your purchase and expense claims require two authorised people to approve them.
Just as single-stage approval lets any authorised approver sign off a request, so two-stage approval lets any TWO approvers sign it off. It could be a combination of one of three mangers on a given team plus an admin user or some other combination.
See our guide to who can see and approve requests for more details.
We are often asked if we can support a situation where a request has to be signed off by, say, a line manager first and then by a finance manager.
Because Turbine allows any two authorised approvers to approve something, it's not possible to automate this flow. However, it is very easy to do this on a human informal basis if the senior manager / second approver just waits until they see the first approval on the dashboard and doesn't approve anything that hasn't already been approved by someone else first.