I've been at DAL for awhile. Here are some answers.
When you drop a trip off your schedule to another pilot, how is your guarantee affected? In other words, lets say you end up with a 75 hour line and drop a three day worth 15 hours to another pilot. Is your pay now 60 for the month?
Correct. There really is no regular line guarantee at DAL (there is in theory, but it rarely if ever comes into play). PBS will build you a line, which could range between 65 and 89:30 (not in the same month, but those are the two extremes of the Line Construction Window, depending on the month; month to month ALVs never range more than 15 hours). You could drop a line to ZERO and get paid zero--but also owe nothing to the company. In fact I recently flew with a captain that dropped every trip for two months so as to work with his wife on her catering business.
The only issue you get with perpetually doing that is at some point you need to get your 3 takeoffs and landings every 90 days; it might be hard to explain why you haven't done that when you drop everything for three months straight and you were holding a regular line.
Also, does the trade board allow line holders to drop trips in to open time? How about pick up trips from open time?
There are two separate issues here. One already mentioned is the "Pilot to Pilot" Swapboard. This is accessed via the DAL computer, but is entirely between pilots. You can offer up a trip of yours for another pilot to pick up, offer a trip of yours for a swap, or vice versa. I have done all four.
Entirely unrelated is the open time in the company computer. You can attempt to swap with open time (or put in a blind swap hoping a trip might pop up into open time) or you can attempt to drop a trip into the pot. If reserve numbers are good, then the trip will just drop into open time and off your schedule. If reserves are tight, then the trip will remain on your line, but will go into open time with a "Q" next to it, meaning "Qualified." That means that the trip is available for another LINEholder to pick up, but until that happens it is still on your line. If no one picks it up within 48 hours of report, the trip is taken off the open time list and remains yours.
So...if a pilot really wants to get rid of a trip, it would behoove him to BOTH put it up for "pickup" on the Swapboard AND try and personal drop it via the company computer (known as DBMS). Some pilots check one without the other, and vice versa. Using both venues increases your odds of getting your desired result.
What about reserve guys, can a reserve pick up a trip from open time?
Unfortunately no. A reserve can try and specify what kinds of trips he would like to fly if called upon, but even that is nebulous. You cannot just call scheduling and say "I want to fly trip such and such tomorrow" and
have it happen.
Good luck at DAL!