manifester bedeutet auf Englisch

demonstrate [demonstrated, demonstrating, demonstrates]▼◼◼◼(to participate in a demonstration)
verb
[UK: ˈde.mən.streɪt] [US: ˈde.mən.ˌstret]Thousands of people are demonstrating. = Des milliers de personnes manifestent.

vent [vented, venting, vents]▼◼◻◻(to express a strong emotion)
verb
[UK: vent] [US: ˈvent]

flag down▼(use a signal to get someone's attention)
verb
[UK: flæɡ daʊn] [US: ˈflæɡ ˈdaʊn]