You need the "again" keyword.
use myInvoice again alias myInvoice_rpt
or if it's just for a report you could do
select * from myInvoice into cursor myInvoice_rpt where ...
If myInvoice is a View that contains only the rows for one invoice you can do away with the WHERE clause.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1