Car rental reservation in &1 on &2 from variant &3 is confirmed

What causes this issue?

Your car rental reservation has been confirmed by the provider. Your
travel plan has therefore been updated.

System Response

In the request details you now see the relevant reservation number.
This reservation number serves as identification, if you want to have
changes made to your reservation.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.