If you feel they are sincere and want to know the truth and if you are knowledgable and capable of understanding the Quran and sunnah properly in order to call them to sunnah, this is permissible. Otherwise, you must not debate them.
If you feel they are sincere and want to know the truth and if you are knowledgable and capable of understanding the Quran and sunnah properly in order to call them to sunnah, this is permissible. Otherwise, you must not debate them.