what practical methods exist to enable the teams to trust their new approach and not revert to old thinking?

I have worked with many teams over the years that process applications for housing benefit in the UK, in the main they have understood the key principles they need to follow in order to add maximum value to their customers, they find new and innovative ways to delight their customers and are in general happy with the new approach to the work.

One of the key issues that keeps cropping up again and again is whilst the is still an inherited backlog of work, i.e. Before capacity levels with demand, some teams find it very difficult to see past the backlog and the failure demand it causes they therefore find it easier to revert back to old habits in terms of trying to manage the work and the staff.

To address this problem I work with the teams and their leaders to focus on delivering value to customers and trusting that the backlog will reduce given time, whilst this has worked on many occasions, sometimes it is less successful. The question this poses is "what practical methods exist to enable the teams to trust their new approach and not revert to old thinking?"