Is it possible to change the project settings of an already existing project?

For example changing the parser rule, the directory for the source files, or the target path rule?

Reason: A new attribute has been added to my files in the project so the parser rule has to be adjusted. In another project, the directory for the source files has changed and as a result I would like to adjust the path to the source file and edit the new target path rule accordingly.

If it is possible to change the parser rule for an already existing project, how can I apply the rule to all the files in the project instead of assigning it individually to each file?