Answer:

F rising to B is now and forever an augmented fourth, of course, and B to F will remain a diminished fifth. But "Fa" and "Si," if you're referring to the "movable Do" system used in the United States, refer not to specific pitches but rather to the fourth and seventh degrees in a major scale. In countries that use the "fixed Do" system, such as France, "Fa" and "Si" are just synonyms for F and B.

All transpositions of the major scale have an augmented fourth between the fourth and seventh degrees. All transpositions of the natural minor scale have that interval between the sixth and second degrees. All the church modes have that same interval, in a different location for each.

But if you ask: which standard scales have an augmented fourth between their fourth and their seventh degrees, then the answer is: major, harmonic minor and ascending melodic minor.