You don't need a new accent
what the examiner actually listens for
The band descriptors never ask for a British or American accent. They ask how clear you are and how well you use stress, chunks and intonation.
IELTS Band 8 Pronunciation, in plain words: easy to understand all the way through,the target and your own accent barely gets in the way.not "no accent"
Aim for clear, not a new accent.