Rigidly attached to routine

Before You Begin
Pause and breathe. Even if this shouldn't be happening... accept that it is and embrace it with composure and calmness.
Calmness is the only way forward because without calm, there is no possibility for receptiveness and connection. Your child won't give to you any more than they see from you.
Never forget that a strong connection is fundamental, as there will be no correction in them if there is no connection with you.
The Core Problem
They feel that moving away from the familiar or predictable will bring problems.
What Will Make It Worse
Forcing the child to deviate from their routine abruptly, or reacting with frustration when they struggle to be flexible, will only worsen their emotional state and make them further yearn for their safe routine.
What The Child Needs
1. To believe that you want them to succeed as much as they do: Being able to go along with something outside of the routine is a helpful life skill, and they will end up showing themselves a new way to succeed.
2. To break the thought pattern that "something different = something bad": Help them see that different can be fun and exciting.
3. To feel the satisfaction and empowerment of handling the unexpected things that come up that require a new approach.
How To Have The Conversation With Your Child
Find a time and place where the child feels comfortable to talk without distractions.
Use empathy and active listening to better understand why the child does things a certain way, and show that you genuinely want them to succeed.
Listen without interrupting, so the child feels heard and validated. Avoid judgment and criticism during the conversation.
Seeing their perspective and feelings being taken seriously is key for the child to be open to a change.
Even if it doesn't all happen in one conversation, start acting on the provided list of items that the child needs.
Ideally, collaborate with the child to set positive behavior goals and offer support in achieving them.