Knock

The knock spell will open stuck or held or wizard-locked doors. It will also open barred or otherwise locked doors. It causes secret doors to open. 

The knock spell will also open locked or trick-opening boxes or chests. It will loose shackles or chains as well. 

If it is used to open a wizard-locked door, the knock does not remove the former spell, but it simply suspends its functioning for 1 turn. 

In all other cases, the knock will permanently open locks or welds — although the former could be closed and locked again thereafter. It will not raise bars or similar impediments (such as a portcullis). 

The spell will perform two functions, but if a door is locked, barred, and held, opening it will require two knock spells.