While saying Salah in the mosque with congregation a person remembers that the coat he is wearing is not Taahir (a child urinated on it). What should the person do then?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Whoever finds some impurities on his clothes during the prayer, he should take off the garment on which there is impurity if possible. Otherwise, the person stops praying, cleans the impurity or wears another pure garment and repeats the prayer.

Allah knows best.