So you're saying the S slug is out of alignment compared to all the others? A type sample would be very helpful, but assuming that all the other letters (lower vs. uppercase) are correctly aligned, it sounds like that particular type bar might be bent and needs to be shortened (through corrective bending). This type of work takes some finesse, and specialty tools such as a throwover and a mauler make it easier, but if you're work making very small adjustments, and take your time, it might be something that you can fix on your own.

A great way to test the alignment on your machine would be to type these two lines out:
AMARANATH SASESUSOS ORONOCO INITIATION SECEDES URUGUAY PHILADELPHIA
amaranath sasesusos oronoco initiation secedes uruguay philadelphia

 

In a situation like this it is often the case that the type slug has been soldered on a little too high (or, more likely, re-soldered, since it couldn't have left the factory like this). Compare the problem one with its neighbors, looking at the way the slugs fit the ends of the typebars. If this is a correct analysis, the fix is to re-solder the slug in the right place and angles; this is not very easy to do so I recommend a trip to a professional.

OTOH, it's possible, though unlikely, that someone might have replaced that typebar with an incorrect one. Often the bars themselves are numbered sequentially across the segment; check that sequence.

HTH