Help with knotted rope

Last evening my family and I were out riding and after I fell and I was waiting for the handle to come by, I notice there was a knot about halfway in my rope. I tried getting it out on the spot, but it was already so tight from me riding on it that I could not manage to even loosen it. Does anybody know any tricks for removing knots from ropes? I think its a dyneema rope, it is from the proline LG rope/handle combo.

Thanks in advance for any help!