A man who carries a flag, especially one used for signalling.
A man who raises a flag.
"The Bands played the National Anthem and the Royal Standard was cracked by the Flagman and flown beside the clocktower at the top of the Horse Guards building."https://www.army.mod.uk/news/splendour-and-precision-from-the-british-army-for-the-japanese-state-visit/