Regarding Apollos, the Bible states:
Acts 18:25 (ESV Strong's) 25 He had been instructed in the way of the Lord. And being fervent in spirit, he spoke and taught accurately the things concerning Jesus, though he knew only the baptism of John. 26 He began to speak boldly in the synagogue, but when Priscilla and Aquila heard him, they took him aside and explained to him the way of God more accurately.
However immediately after this episode we read of another set of believers only familiar with John's baptism who were then baptized in the name of Jesus:
Acts 19:3 (ESV Strong's) 3 And he said, “Into what then were you baptized?” They said, “Into John's baptism.” 4 And Paul said, “John baptized with the baptism of repentance, telling the people to believe in the one who was to come after him, that is, Jesus.” 5 On hearing this, they were baptized in the name of the Lord Jesus.
Should we see these two episodes as complimentary and understand that Apollos was similarly baptized in the name of Jesus? Or should we instead see these as contrasts, and understand that Apollo was not again baptized?