Word for making a tentative meeting non-tentative (meaning it will definitely go ahead)

I am looking for a word for removing the provisional or tentative property of something, in particular meetings.

I would like to use this in the context where I set up a provisional meeting and anyone from a group can make it "definite" and the meeting is going ahead.

Is there a word to describe that action or the outcome (even saying a meeting becomes "definite" does not sound right)? Ideally it would be a word that can be used in a professional context, i.e. most people would know what I mean if I use that word.

An example sentence could be:

"I have set up a tentative meeting for 2pm. It can be ??? by anyone present if the situation deteriorates."

or perhaps

"I have set up a tentative meeting for 2pm. Anyone present can declare it ??? if the situation deteriorates."

Solution 1:

I would use made definite in your first example and definite in your second.

"I have set up a tentative meeting for 2pm. It can be made definite by anyone present if the situation deteriorates."

"I have set up a tentative meeting for 2pm. Anyone present can declare it definite if the situation deteriorates."

I have often encountered these words in a professional context. There is no better antonym for tentative than definite when it comes to meetings.