Is the guest service (relation) officer higher then receptionist position?

yes 

1- to ensure the gust membership tire

2- the member is eligible for all in hotel benefits including complimentary

3-to ensure an communication and a complete

 service delivering to the gust

4- know all problem about the gust and ensure it resolved .

5- make sure the gust satisfy before live the hotel  

6- sale some think (party-diving - trip) 

Yes it is

May be because the move around alot and ensuring guest are registered for membership their profile are well profiled, air ticket reservation some times they act as receptionists, concierge clarks.