Of the Interpretation and General Clauses legislation; which is part of Malaysian statutory law. It provides, inter alia, that where a power to appoint exists there also exists, unless specifically provided otherwise,, a power to dismiss.
The Constitution specifically provides for the Agong to appoint a Prime Minister and it follows the he has the power to dismiss anyone so appointed. This may smack of Stuart determinism but it is, never the less the current law of Malaysia.
Given the Moo no longer has, if he ever lawfully had, a majority in the Assembly it is open to the Agong to use the power of dismissal inherent in his power of appointment. No need for delay. A simple stroke of the pen suffices.