A mate linkset cannot be assigned to a linkset that already has an assigned mate linkset.
Recovery
Display the mates of specified linksets. Enter the rtrv-ls command.
The MATELSN heading displays linkset mates.
Change the assigned mate linkset as necessary. Refer to the Database Administration - SS7 User's Guide (SS7 linksets) and the Database Administration - IP7 User's Guide (IP linksets) for assistance.
Re-enter the chg-ls command that generated this error message.