Is it possible to modify an object(time series) in a model?

I implement a list object in R. Is it possible to re-assign an object inside this list? The object I have to re-assign is a time-series.

forecast_list <- list(
  model = NULL,
  method = "LSTM",
  mean = forcasted,
  x = kt,
  fitted = predicted_total,
)

HerecI would like to do:

forecast_list$mean = time_series