flagman

noun2

1. •
   A man who carries a flag, especially one used for signalling.

   • At the approach to Southampton Terminus, double track branches off to the left, runs alongside the platforms and then cuts across Canute Road on an open crossing under the protection of a flagman. — 1959
2. •
   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/