Database server migration

HI Experts,

Recently we are trying to change the database server , which means all the versions of database and OTM remains same, only the server is going to change. Hence the database name is changed now with new TNS names,
Could you please let me know which are all the areas I need to change so that I can point to the new database.

We have 2 web,2 app, 1 report server

OTM version:5.5
Database version:10g