It is important to establish a higher aspirational goal for a brand. However one of the risks in repositioning a brand is abandoning the position that established them as a real force in the marketplace, in favour of an aspiring position for which they haven't yet earned credibility. The problem here lies not so much in extending the brand position, so much as abandoning the position that you already own in the mind of the market before clearly staking out a new position. This can leave your brand in no-mans land.
As we always insist, a brand position needs to be credible. Part of that means sitting in a place between what you're saying, and where you'd like the brand to be; what your audience currently believes, and what the audience would value. It's about balancing the experience of the brand, with the promise of the brand.
Good positioning should exist somewhere in the centre of these requirements. If your brand is positioned only by what customers believe, it won't ever grow. If it's positioned too far towards where you hope it will go then it won't appear credible. This balance needs to be treaded carefully to reinforce who you are in customers minds, as well as to nudge the brand to where you want to take it.
When you have succeeded in moving the brand a little closer to where your aspirations see it, it's usually not helpful to leave behind your old positioning. If you've spent years of work earning a particular position in the market place, then rather than denying that position it's usually much better to build on it. Don't turn your back on it because with a well developed positioning strategy you'll be able to extend the brand, turning your old brand position into a credible brand story.