From a reliable anonymous source.
Three terms:
Down/Lateral Bid: an award of a different crew status that is compensated at an hourly rate less than or equal to the hourly rate for the pilot’s current crew status. (CBA 24.E.1.a.)
Down/Lateral Bid RESTRICTION: (Unless waived blah blah blah ...) a pilot may not receive a permanent vacancy award based on a down/lateral bid unless he has been in his current crew status for at least 18 months. (CBA 24.E.1.b.)
Down/Lateral Bid FREEZE: A pilot who is activated ... based on a down/lateral bid shall be frozen in that crew status for 24 months, commencing on his actual activation
date. (CBA 24.E.1.c.)
One pertinent exception: A pilot subject to a down/lateral bid freeze or restriction is eligible for an award or assignment of his crew status at a new base. (CBA 24.E.1.d.i.) [Note it says "his crew status," not a new crew status. This would allow a 757 FO in Memphis to be awarded 757 FO CDG, but not 727 FO.]
The RESTRICTION applies before a pilot can down/lateral bid, the FREEZE occurs after the down/lateral bid, and they can both be waived for a new base (same crew status).