You can set up a periodic Task (weekly or monthly) which will pop-up as a reminder to remind you to generate a status report for all software licenses set to expire in a few weeks.
Every technician in charge of a certain Asset or customer can add Tasks with pop-up reminders from the Pending tab of the Asset. For example, you can add a Task for the Asset and set a reminder to pop up 4 weeks prior to the expiration date, and another one for two weeks prior to the expiration date.
Note that you can send an email from the Asset window (using the Email icon on the tool bar) which will automatically copy the Asset information into an email which you can send to the customer as a reminder to renew the licenses.