# What is the effect of using survey sample weights for a sub-sample?

If a sub-sample of the survey sample, selected based on certain demographic characteristics of the data (e.g. age, race etc.), is used, which means the sub-sample might not be representative of the population anymore, is it better to not use original sampling survey weights provided or is it still better to use the survey weights calibrated for the original survey sample data?

P.S. If I choose to generate my own weights based on a sub-sample data, what is the best methodology for this, and could someone please point me to the references that might be helpful?

If the option of generating own weights isn't available, what would be the second best option?

new_subsample <- subset( full_sample , some_demographic_group == TRUE )