How to change wording on packing slips?

[gerbereg_lrhced]

Hello.

My packing slips keep thanking my buyers for their purchase of a hat, regardless of what they have purchased! How do I change this?

Thanks in advance.

[wooden_flower]

When you click print packing slip and more, a window opens where you select the document you want to print.  Under packing list is ‘customize’. Click there to select from a list of optional messages, or a custom message.