Humans are not receptive to change. Big change creates resistance. Resistance breeds system failures. With Agile enhancements, change can be mitigate greatly. This is done by gently introducing enhancements with small Agile changes.

Agile with Canary Release
One of my favorite Agile enhancements method is canary release or aka feature toggle. This change is gently introduced to users via toggle options. Sometimes, backward compatible is provided to ease the users toward the new feature. In other cases, canary release is done to a select group of pilot users or country.
Tweaking Resistance
The wonderful thing with Agile is the amount of tweaking you can do with user resistance. You can adjust your enhancements accordingly to the user resistance encountered instead of blindly forcing through your change. Agile also provide the flexibility to scope your enhancements with users. If you face a lot of resistance, do be proactive and reduce the change impact. Being reactive will result in a failed enhancement because users will choose not to adopt the new feature.
Users behaviors are getting adapt and sensitive to system changes. When users become more used to system flow, they will provide greater resistance to any new change. You will want to adopt Agile enhancement to reduce change impact.