4f55f5cb_ISDN_Cause_Codes__Cause_Usage
[Cause#] 22 [Fixit!] N/A [Cause Summary] Number changed. [Cause Usage] 
Returned to a calling user when the called party number indicated by the calling user is no longer assigned. The new called party number may optionally be included in the diagnostic field. If a network does not support this capability, cause No. 1, unassigned (unallocated) number, shall be used.
ISDN Cause Codes
Cause Usage