All too often culture change is something people are told is necessary and they are told what is going to happen to achieve changes and how they will be impacted and what they are expected to do differently. This approach tends to be resisted. People immediately identify the aspects of their current culture they like and identify any change as change they do not want to happen. Any change they think needs to happen is often identified as changes others need to make, not them. There is no ownership for change.
When you involve people in identifying the current culture, saying what they feel about this and how it is affecting them and business outcomes they start to identify for themselves the need to make changes. When you also involve people in identifying the ideal culture for the organisation, the gap between the current and the ideal emerges. People then become very motivated to identify what needs to change in the organisation and in themselves in order to achieve this ideal.
Identifying the current and ideal behavioural norms in your organisation can be very engaging and also provide very robust measures for you to appreciate just how much change there is and exactly where the changes are. Rather than take a scattergun approach to changes and make these relevant to the entire organisation, even if they are not, I recommend you work with your teams to get exact, prioritise and ensure the best return on your investment.