Releasing the dust bowl (Fig. O, P)

Note: The dust bowl can be released either from the unit while
it is in chassis mode, as shown in figure O, or when being
used in the lift away canister vac mode, as shown in figure P.
- Press the dust bowl release lever (20) down to release the
dust bowl.
- Free the dust bowl (5a) from the lift away canister vac (5).
- Using the dust bowl handle (21) and holding the unit over
a suitable waste receptacle, press the dust bowl release
button (6a) to release the dust bowl lid (6) and push the
compacting handle (19) down to empty the contents of the
dust bowl (5a) as shown in figure Q .

Further details can be found in the operating instructions

https://service.blackanddecker.co.uk/i/BLACK_DECKER/GLOBALBOM/GB/CUA525BHP/H1/Instruction_Manual/EN/CUA525BH_CUA525BHP_CUA525BHA_H1_GB.pdf