Tushemerirwe Joan

Hi, I got a bank role part time with nhs as I was looking for another job. I then got a new full and started working there in March. Thing is I was put on the br tax code on this new job and yet when I started this new job, I stopped earning anything from nhs as I did not have time to work there anymore. My question is if I leave the nhs job since I don’t earn anything, does my tax bracket change and can I get a refund for the three months I was only receiving one income and being taxed on it?