Looking at your models on Turbosquid I suppose you know your way around a modeler - make a backup copy of the base OBJ the figure is loaded from first, then load the base OBJ in your modeler, delete the bow tie, re-save the OBJ.  Depending on how accurately your OBJ importer works, you may have to take extra steps to retain polygon grouping information so that the bones still work.  The UV space that the bow tie took up will of course end up being wasted.

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