Web fee waive for one-off event

We've decided that one night of an upcoming production will be a special-industry night, and as part of our offer to this industry, we want to waive our normal web order fee for this night only, but not for other performances of this production. Has anyone done this before? If so, how? Is there a way to do this in Tess or do we have to do this through our website provider (we are not TNEW clients)? 

I'm new to managing events in Tess - thanks for the help!