These cover changes to dates of travel, class of travel, name changes either prior to or after commencement of travel. All fares and tickets carry different restrictions regarding these. Many cheaper fares will not allow any changes at all, whilst most fares will require payment to cover administrative costs in the form of an amendment fee.
6.1 Definition 6.2 Drafting of amendments to Bills 6.3 Some rules relating to amendments
Suggested changes that may clarify, restrict, expand, correct, or otherwise modify the bill as printed.