Open the Administrator Tools menu.
Click the Approval Chains button.
Find the approval chain from which you want to change the order of its users.
Click the manage approvers button.
Find the Required, In-Sequence Approvers group.
Grab the handle on any approver to drag and drop it in the desired order.
The approvers are set in the indicated order immediately upon dropping.
Removing a user from an approval chain will not affect any approvals previously submitted to the chain.