Readjusting the logo to meet new demands
Over time, the originally designed logo may fail to meet all of the technical requirements.
For example, a company's logo may be ill-suited for animation. The company is planning to open a new business segment, and to solicit this new segment, advertisements on TV and in the cinema are very important. This is, however, where the logo is to be employed.
The logo does not (or not fully) meet these requirements, therefore it must be modernized.
Another example is corporate design clothing: A corporation decides that all employees have to wear service clothing. The logo is to be placed on that clothing.
The technical requirements of an embroidered logo are not met by the old logo (logos that are rich in detail cannot be embroidered, or important details may be lost), so an update is commissioned. (There could also be a separate version of the logo, the example is fictional.)