It would be nice to know when someone has reserved an asset by having the help desk send an email to the support group or at least a tech. That way it's not a surprise when someone shows up to pick up a laptop or something.
Get familiar with processes in WHD. Action rules are a great way to customize WHD to various "if this than that" functions.
Web Help Desk Help Processes
Web Help Desk Help Action Rules
If you know of a way to trigger an Action based on an asset reservation action, share it. Linking to the manual is less than helpful as we've already RTFM. I've been pulling my hair out trying to figure a way.