Changing specility

I have got a training post in geriatrics to start from Feb 2023.
I choice of speciality is endocrinology and I was successful in the interview but couldn’t secure in my geography in the last 3 years despite being successful in the interview due to limitations in geography.
Can I change to another speciality ( Endo)whilst being in training in geriatrics?

You should be allowed to apply for the next training year despite having been employed in a training post. There is no restriction from HEE

Thank you for the reply. Do I have to inform my educational supervisor before applying? I am worried about whether that would leave a bad impression.