Hi @alanoztime ,
Welcome to the community!
We'd like to clarify if you wish to change the e-mail address associated with the account or the e-mail address for the Community Log-in.
For TPG account you simply need to log-in to 'My Account' (https://www.tpg.com.au/myaccount)
and got to 'Updatet Contact & Payment Details'
For the Community Log-in, feel free to send me your preferred e-mail address and I will update it for you.
For reference: How do I private message (PM) in the community