ReplaceColor

app.command.ReplaceColor {
  ui=true,
  channels=FilterChannels...,
  from=Color,
  to=Color,
  tolerance=0
}

ui: Show the dialog on the screen, true by default. Set to false for automatic replacement without asking to the user for the change. When the dialog is displayed to the user, app.command.ReplaceColor() will return a true or false value indicating if the replacement was accepeted or cancelled respectively.
channels: A combination of FilterChannels with bitwise OR (|) operator. The default value depends on the active sprite color mode:
from: Color to replace (it's the foreground color by default)
to: Color to replace (it's the background color by default)
tolerance: Maximum allowed difference between from and the pixel in the image to apply the replacement.