I need advice.with my 3 year old.

RiRi • 24 years old with 5 year old daughter, 10 month old daughter and pregnant with baby number 3 after TTC for 2 months!!
My daughter is 3 and has a HUGE knot in her hair and I cannot get it out no matter what I try. She always screams and cries but I don't want to cut it she has long hair. I have tried leaving conditioner in while I try to brush it but that was a fail also tried pulling it apart a little with my fingers and that.failed too please any advice would be greatly appreciated.