The sequence of approval channels is used to determine how stop channels work. Once submitted for approval, the invoice looks at each approval channel in the order set. 

Please note that invoices that match an approval channel will hit all the relevant approval channels concurrently.
To Change the Sequence of Approval Channels:
 1. Go to Settings.

2. Go to Invoice Settings.

3. In the Approval Channel settings, select the legal entity.

4. Click 'Edit Sequence' in the top right corner.

5. Click and drag the approval channel to it's desired order. The black bar shows you where in the sequence you're dropping the channel.