You can simply update your gender selection in your Tend app under Account settings.
Click Account on the bottom navigation bar
Click your name under Profiles
Change your gender on the 5th line under Personal Details
You can also add in your pronouns
Any gender selection update in your Tend account won't be reflected in your NHI record automatically.
If you wish to make a change in your NHI record, you will need to contact the Ministry of Health directly on 0800 855 151.
Please reach out to our Customer Experience Team if you have any further questions, we will do our best to assist you.