How can two names have the same referent but different senses in Frege’s theory?

In the philosophy of Gottlob Frege, the distinction between sense (Sinn) and referent (Bedeutung) explains how two names can point to the same object while providing different information.12

The referent is the actual object or entity to which a name points. The sense, however, is the "mode of presentation" of that referent—the specific way in which the object is described or identified. Because different names present the same object through different perspectives, they contribute differently to the overall thought expressed by a sentence.2

For example, "the Morning Star" and "the Evening Star" both refer to the planet Venus. While they share the same referent, they have different senses because they present the planet via different observational contexts. This explains why an identity statement like "the Morning Star is the Evening Star" can be informative, representing a discovery, whereas "the Morning Star is the Morning Star" is trivial. The distinct senses allow speakers to grasp the same object in different ways, making the names non-interchangeable in terms of the cognitive content they convey.12