I haven't a clue what "to make a change of front" means unless it's something military. But then I'm English and maybe it means something to an American. For the German "vom Saulus zum Paulus werden", I'd say "to have a Road to Damascus experience" or "to have a Damascene experience".

I was also going to say that I have no idea what the English expression is supposed to mean, and don't believe I've heard it in AE.

Pons-Collins:
Saulus - (Bibl) Saul
vom Saulus zum Paulus werden - (fig) to have seen the light

How about this? Makes sense to me, though it didn't occur to me either until I looked in the dictionary. I don't want to throw it up there in boldface though unless someone else agrees.

Glad to join the consensus that '(make a) change of front' is not a real expression AFAIK. (Had exactly the same thought about military, but even there it doesn't sound at all plausible: Say, boys, we're not doing too well on the Western Front, let's go fight somewhere else...)

'(Have a) change of heart,' though, might be another option. An outside shot might be something like (Mr.) Hyde to (Dr.) Jekyll, but that's really usually the other way around, or else both together: Jekyll-and-Hyde personality.

A 'road-to-Damascus experience' seems not unreasonable, but I'm not sure I'd list it in the dictionary as a fixed expression. 'Damascene' seems to have survived longer in BE; in AE it's understandable as historical or literary, but in normal usage really only lowercase: (looking like) decorated metal.

I've belatedly just looked at the existing LEO entries and seen 'make a volte-face,' which is also close (though fairly elevated diction, possibly even worth marking [formal]). Drawing on that you could also consider 'do an about-face,' or perhaps even 'flip-flop' (v.) [informal]. However, all those often have the slightly negative connotation of inconsistency, unpredictability, changing one's mind; that doesn't fit ideally with the Acts story, but it may be okay with the metaphor in modern German.

A more positive related idea: 'turn over a new leaf.'

One listing of idioms has 'vom Saulus zum Paulus wandeln' instead of 'werden':
http://www.redensarten-index.de/suche.php4?su...

'See the light' is more toward sudden realization (arriving at an endpoint) than drastic reversal (making a 180-degree turn). I'm not sure it translates back the other way very reliably, or at least, it would be good to include some other translations too:

Oxford-Duden:
see the light (fig.: undergo conversion) - das Licht schauen (geh.)
I saw the light (I realized my error etc.) - mir ging ein Licht auf (ugs.)
he'll eventually see the light (he'll realize the truth) - ihm werden die Augen noch aufgehen

Pons-Collins:
finally I saw the light (inf) - endlich ging mir ein Licht auf (inf); (morally) endlich wurden mir die Augen geöffnet

Könnte man das deutsche 'die Fronten wechseln' nicht mit 'to change sides' übersetzen (ok - es gibt im Deutschen auch 'die Seiten wechseln', aber das meint ja ohnehin das Gleiche)

Dialogue on Catholic Soteriology:
My God [note the implication that Catholics, and even Arminian Protestants, worship a different God] on the other hand, can even effect the "total turnaround" of someone like Saul of Tarsus.......

Saul's "conversion experience" on the road to Damascus.

A definite conversion experience: a definite point in your life when you turn your back on the world, on its value-system on its attitudes and viewpoints, on all that is unclean and impure and wrong, and go God's way; a point in your life when you do an about-face.....

http://ic.net/~erasmus/RAZ131.HTM
http://pages.prodigy.net/jmiller.cb/a156.html

For those of you who guessed the military connections:

change v.
9(b) (also to change feet.) = to change step. to change front: (orig. Mil.) to face in another direction, to alter one’s direction of standing or marching; usually fig.
[OED2]

change
–v.t.
18.change front, Mil. to shift a military force in another direction.
[Random House Webster's Unabridged Dict.]

Ah Doris, das ist erhellend. Und anscheinend ein falscher Freund. Die Fronten wechseln heißt ja soviel wie "zum Gegener überlaufen". "To change front" bedeutet je nur, in eine anderen Richtung zu agieren, aber immernoch mit denselben Leuten.