(1A3A) Shift your identity by changing your actions
If I do, so I am, AND I am, so I do.
Then it follows that changing what you do can change who you are.
This might take a while. You'll need to fight off the effects of cognitive dissonance, minimising, etc. But you can use current and past actions as proof that your identity has changed.
graph LR A1[I believe] --> A2[I am] A2 --> A3[I do] A3 -- interpet --> A1
Prev:: (1A3) We act out our identity
supports:: (5A2A) Take Small Visible Actions