Once your model is created and trained, you can use this model to predict outcomes for new, updated data. For instance, if you trained a new propensity model using last year's customer and prospect data, you will likely want to predict propensities for new prospects that were not known last last year. The new data contains the same variables, but different records with new and different values. Your model in predict mode will be able to predict these new outcomes.
However, if you would like to bring in new data in the form of new variables, this will require creating and training a new model before you can use it to predict future data and outcomes.