Like has been said already, Use the 'SET Line Credit Range to LOW' to start the bid group. Then, use the AVOID Work for either specific days or even weeks. But, no matter what you do, you'll have to get at least the minimum hours for your seat/fleet.

If you are a line holder and then want to drop down even further, you can drop trips once the line is awarded and trading opens.

But if you demand that PBS 'AVOIDs' too much stuff, it can't build a line or reserve days at all and then it goes into Completion Mode so you end up with *something* when it's done. And you don't want that.

As also stated, Prefbid.com is excellent. But read the PDF PBS User Guide (under PBS/System Documents) too. Helps explain the commands and how they'll be interpreted.