Thanks for the response. I should have been more descriptive! I would like to change the text of one specific error on the checkout. When someone orders a product but there are not available ways to send, the message that appears in greek is : “Δεν έχει επιλεγεί καμία μέθοδος πληρωμής. Παρακαλούμε, ελέγξτε ξανά τη διεύθυνσή σας, ή επικοινωνήστε μαζί μας αν χρειάζεστε οποιαδήποτε βοήθεια.” –> No payment method has been chosen. Check your address or contact us if you need help. I would like to customize only this text.