How can I switch from Growww?

Hi, I am a student who just started learning about stock market and found out that zerodha is better than groww and I want to switch to it. I already hold some stocks in groww which I don't wish to sell. My question is how I can get a bsda account with zerodha without selling my groww holding. Because if I'm not wrong, I can't get bsda account if I already hold a demat account.