Hi,
If you only want to change the callername parameter then you have to added in the query. If you don't route from the database it would be something like this:
[call.preroute]
query=SELECT contact_name as callername, null as location FROM contacts WHERE contact_phone_number = ${caller}
result=location
or
[call.route]
query=SELECT contact_name as callername, location FROM contacts WHERE contact_phone_number = ${caller}
result=location
id you also have the location in the database
This depends on how the routing is done and if you want to do it here or from another module/script