Are you more junior or senior than the team working on greenfield projects? Management often keeps people in maintenance either because they've stereotyped them

Are you more junior or senior than the team working on greenfield projects? Management often keeps people in maintenance either because they've stereotyped them as too green or too seasoned or maybe just they have pigeonholed you as a backfield/anchor player. Another component is assertiveness. Sometimes you have to make friends with someone on the other project & inject yourself into it. You know, "it's easier to ask forgiveness than permission." The easiest way would be if something from the greenfield project interfaces with or shares functionality with legacy systems you've worked with. If the manager hears from another team member, "Ned is helping us interface with legacy Foo & knows a lot about Bar" then they'll see you bring cross-fertilization skills.