9. Batsman leaving the field or retiring
A batsman may retire at any time during his innings. The umpires, before allowing play to proceed, shall be informed of the reason for a batsman retiring.
(a) If a batsman retires because of illness, injury or any other unavoidable cause, he is entitled to resume his innings subject to (c) below. If for any reason he does not do so, his innings is to be recorded as 'Retired – not out'.
(b) If a batsman retires for any reason other than as in (a) above, he may only resume his innings with the consent of the opposing captain. If for any reason he does not resume his innings it is to be recorded as 'Retired – out'.
(c) If after retiring a batsman resumes his innings, it shall be only at the fall of a wicket or the retirement of another batsman.