What Change was made in the second sentence I always leave a tip a tip I always leave

An inverted subject-verb order

Explanation:

When a sentence is inverted by changing the structure of words hence altering the initial meaning that is an inversion, Even though a sentence is in an inverted format, it should retain correct grammar; the sentence may be inverted to lay emphasis and stress of the matter communicated. Therefore a sentence is inverted to show the uniqueness of an event, and the sentence usually starts in a negative form. Finally when a sentence is inverted the gap of the verb changes is written prior to the subject.