choose the project folder example com.example.app1 and right click -> Refactor -> move... or F6.
check Move package 'com.example.app1' to another package and it may generate warning just choose OK and enter your new path for example 'com.hi.app2' and click ok and it will ask for create a new folder choose ok.
close project from File -> close project
choose open exiting Android studio project
just Delete the all old folders for example here example and app1.
Clean and Rebuild project.
This will update move and rename the project path.