Using the Enterprise edition of Salesforce, I need to write a trigger and am unsure of the code that I need to write. I am just starting to learn about triggers and APEX coding. I want to accomplish the following task which cannot be done via a workflow because the asset object cannot connect to a contact object field (according to salesforce support). 

When the asset field of "License Expiration Date" changes to X date, I want the Contact "Role" field to automatically update
Example is as follows: An asset is a license file in my organization. Asset License Expiration Date field is May 15, 2014. Current calendar date is May 14, 2014. Therefore the license has expired and the customer is no longer a current customer. Therefore, I need to write a trigger to automatically update the Contact Role field from "Current Customer" to "Previous User". Im not sure how to write the trigger coding to make this possible. 

Thanks!

Using the Enterprise edition of Salesforce, I need to write a trigger and am unsure of the code that I need to write. I am just starting to learn about triggers and APEX coding. I want to accomplish the following task which cannot be done via a workflow because the asset object cannot connect to a contact object field (according to salesforce support). 

When the asset field of "License Expiration Date" changes to X date, I want the Contact "Role" field to automatically update
Example is as follows: An asset is a license file in my organization. Asset License Expiration Date field is May 15, 2014. Current calendar date is May 14, 2014. Therefore the license has expired and the customer is no longer a current customer. Therefore, I need to write a trigger to automatically update the Contact Role field from "Current Customer" to "Previous User". Im not sure how to write the trigger coding to make this possible. 

Thanks!