What is the difference between white discharge and the "white story" (al-qissah al-bayḍāʾ), are both of them nullifiers of ablution, and is it necessary to change clothes?

The white discharge (al-qissah al-bayda') is a white fluid that appears after the cessation of menstruation, indicating a woman's purity. It nullifies ablution (wudu'). As for white fluid (as-sa'il al-abyad), it is a broader term, discharged by some women during times of purity, and it also nullifies ablution.