What is the process of retiring from trust ownership and transfer it

About 2 years ago my mother established a Trust. My mother and I are the trustees. She also wrote a Memorandum of Gift which states that her property in Hyderabad will become part of the Trust and gifted to her sons upon her death. Things have changed. My mother wants me to have complete ownership of her property now. As such, my mother wishes to retire/resign from the trust so that I am the only trustee. I understand my mother will have to provide her intention of retiring in writing. Does her letter of retirement have to be formally registered? Will the gift deed need to be updated? Will taxes apply?