user12644: I am just curious. Is it possible for a rated player to quit his association with FIDE and start afresh, as an unrated player?

user11629: I found FIDE regulations 7.21 which state: 

Players whose ratings drop below 1000 are listed on the next list as
  ‘delisted’. Thereafter, they are treated in the same manner as any
  other unrated player.

This sounds like a "reset" to me. 
Note that this is different to an inactive player which you become after not playing rated games for a year. However in the case of inactive players you retain your rating.
Other than this "delisting" I don't think there is a way to lose your rating.

12644: <p>I am just curious. Is it possible for a rated player to quit his association with FIDE and start afresh, as an unrated player?</p>
 11629: <p>I found FIDE regulations 7.21 which state: </p>

<blockquote>
  <p>Players whose ratings drop below 1000 are listed on the next list as
  ‘delisted’. Thereafter, they are treated in the same manner as any
  other unrated player.</p>
</blockquote>

<p>This sounds like a "reset" to me. </p>

<p>Note that this is different to an <em>inactive</em> player which you become after not playing rated games for a year. However in the case of inactive players you retain your rating.</p>

<p>Other than this "delisting" I don't think there is a way to lose your rating.</p>
