Onward clearance - alt restriction
I know this subject has been discussed before, and I've searched for it, but can't find it.
Can anyone quote me chapter and verse (preferably from MATS) on the following:-
An aircraft is cleared on initial descent to, say, FL100, to be level by Point A, say the GWC. Descent starts. Before reaching either GWC or FL100, ATC clear them to a lower level or a further point on the flight plan without restating the level restriction. Is that level restriction thereby lifted?