You can change translations for any language, this includes the default US English. There are two different ways to change core translations:
1. Using theme specific translations
You can define custom translations in your theme, create the following file if it does not exist yet:
en_US if you use a different language)
Note that this should be a project specific theme, not
some_bought_theme/default. If you did not already, you can add a child theme next to
default and specify this one as theme in the system configuration. You don't need to copy anything from the
default directory since Magento falls back automatically, so you only need to add the files that are customized.
translate.csv you can add your custom translations. Since the translated string is "Sorry, no quotes are available for this order at this time." and it's coming from the
Mage_Sales module, you need to add this line:
"Mage_Sales::Sorry, no quotes are available for this order at this time.","your custom translation here"
2. Using the "inline translation" feature
As a store manager you can change translations using the "Inline Translation" feature.
- Add Your IP Address to the Developer Mode Whitelist (System > Configuration > Developer)
- Disable Output Caches (System > Cache Management)
- Activate the Translate Inline Tool (System > Configuration > Developer)
- Update the Text (Click the icon next to any text in the frontend that you want to change)
- Restore Original Settings
This will save the custom translation in the database for the selected store and theme.