change the ownership

Dear sir/madam,
                    I'm Prakash from tamilnadu,India my number is 8754832832 and my avast application is changed to 918973183931please change the owner number to 8754832832.I myself changed the sim card in my mobile at that time my avast application changed the ownership to 897318931.and I don't know how to change in it. If possible please instruct me with clear explanation.
Thanks and regards,
K.Prakash.