On the EMB-145, it is quite simple to change the runway, approach, as well as the STAR transition to the approach. At most the airports in the US the STAR will end 20 to 25 miles away from the airport and have you at an altitude of approximately 10,000 to 11,000. From this point TRACON vectors you onto the final approach course, whether it be a ILS, GPS, VOR, RNAV, or any other approach. In the EMB-145, if the approach is an ILS we have to transfer from FMS navigation to standard navigation using the LOC and GS. If it is a GPS, RNAV, or a NDB or VOR approach with a GPS overlay, we can continue using the FMS for course guidance. However, we will use a heading mode while getting vectors by ATC to the final approach course. For approaches using a DME ARC, Procedure Turn, or any other type of enroute transition to the approach , the FMS will already have the various IAFs (Initial Approach Fixes) programmed into the system. All you have to do is select the specific IAF and the FMS will automatically program the various DME ARC, Procedure Turn, et cetera. It makes it quite easy to maintain positional awareness, and accurate course guidance.