How to use a regression equation?

#1
I have a regression model with 11 predictors developed by a researcher. Among the 11 predictors, in a different dataset, I have 7 of them. How can I modify the previous regression model and account for the 7 predictors only? I know I can develop a new regression model. However, I want to know whether there is any method available that accounts for this without a new regression model.