If I am going to play/gm a free rpg day module (Risen From the Sands, in this instance), are players required to use their own character if they have a character in range they are applying it to, or can they play one of the scenarios pre-gens and apply to a PC within range?
If that's confusing, here's an example
Bob is playing Risen from the Sands. Bob has a PC, Luke Sandwalker, a 2nd/3rd/4th level gunslinger he want's to apply credit to, but wants to play the included pregen, Quinn. 
Is Bob allowed to:
a) play Quinn and apply it to his gunslinger (assuming it's level is 2,3 or 4)? 
Or must Bob choose to: 
b) apply credit to a different character (his level 1 PC Frodo Bilgins, the halfling rogue) 
c) play his gunslinger