How to create a part with 2 footprints?

[jg_geadinc]

 i.e. it would have 2 pin 1s, etc. so either of two different parts with the same pin numbers but slightly different footprints can be used.

[dbur]

I usually put both parts in my schematic and then place the prefered part in UB and lock it.  Then I place the alternate footprint as desired, and just live with the design rule error that gives you.

You can't have two pins with the same name.  You could have a 1a, 1b, 2a, 2b, ...  if you really want to do a dual footprint part.  In the MS library part edit mode just hook footprint pins 1a & 1b both to schematic pin 1, etc.

[jg_geadinc]

I solved it a different way. For the second part I added Vias for the pads instead of using pins. The pins were close enough where I could make the pads large enough to slightly overlap, although I think I could have connected them using a copper shape/area. Ultiboard assumed the correct net for the vias so copper planes did the correct thermal relief to them and everything. Best of all, no DRC errors.