Have Flow Call itself in a "re-entrant" way

[hilary_stoupa]

The guidance on migrating from SPD 2010 workflows says:

• 30-day run limit for flows: While SharePoint Designer workflows can run endlessly, Power Automate flows have a 30-day lifespan. You can get around this limitation by having your flow call itself in a re-entrant way to restart the time interval.

Can someone explain to me what "having your flow call itself in a re-entrant way" means, practically? I understand that the general idea is that the flow would restart itself when the 30 days lapses, but I don't understand the correct way to implement that.

And will that keep an Approval action alive? Or is the idea that one would just create a new Approval item? Is there then a way to clean up the expired Approval action?