Without specs, or perhaps the schematic so we can see what is required, yes it can be hard.
It's a bit like having a bolt and looking for a replacement without knowing the size, thread type, length, material, etc.
edit: If the circuit os not very demanding of any particular parameter, then yes, you may be able to replace it with something that is not a direct replacement. Of course we don't know it's actually a PNP transistor (presumably you do)