To remove the drawstring of Nike schoolbag, you can follow the following steps:

1. Find the knot of the drawstring and untie it.

2. If the slippers have no detachable parts, it may be necessary to cut the knotted drawstring with scissors or blades.

3. Pull out the rope slowly.

Please note that the drawstring of some Nike schoolbags may not be easy to remove. If you still can't successfully remove the drawstring after trying these steps, I suggest you consult Nike customer service or professional maintenance personnel.