Can celestial be swapped for fiendish using Summon Monster speels?

[Thurbane]

I'm sorry, but it looks like RAW says "No!":

One possible solution there is Purify Summoning [exalted] feat (Dragon #353):

Each creature you conjure with any summon spell gains the good subtype, and creatures that are not already good in alignment become good.

Thank you, I was previously unaware of this feat.