More details please. You are an intern now? By "switching specialties" are you planning to quit the program early or finish out your intern year and start somewhere else in July 2021?
In either case, the first thing you need to do is be REALLY sure you want to leave the program. If you are 50/50 or if there is a chance you may change you mind in a few months I recommend sorting it out BEFORE talking to your PD. This is because as soon as you mention leaving to your PD you become seen as a vacant spot. Depending on the size of your program you may need to be replaced and this is a pain in the ass for the program. Ultimately, you need to do what's right for you but out of respect for your PD let them know as soon as you decide for sure so they can make plans to recruit a 2nd year to fill your shoes if necessary.
In my Res program there was an intern who told our PD in Sept that he wanted to switch to FM. He got our PD's blessing and sent out applications. He tried to change his mind a few months later but found they had already scheduled interviews for his spot for next year and wouldn't let him stay. He was bitter about it but finished up his intern year with us. If I recall he ended up matching to a FM residency in the middle of nowhere.