Renewing the logo is a double-edged blade that refreshes the brand when done right and carries it to a new era; when done wrong, it erases years of accumulated recognition overnight, so the first question should not be 'how', but 'is it really necessary'.
Rebranding makes sense in a number of situations: when brand positioning really changes, when the logo is technically behind the age (unless it works in digital), or when the brand is referred to with an unintended perception. Just saying 'we're bored' is not a good reason.
The right approach is usually evolution, not revolution. Maintaining the brand's recognized core and simplifying it, updating it, and making it digitally viable; it provides both freshness and continuity. A good rebranding aims for the customer to say, 'This is new, but it's still them.'