If the first pass at constructing an event budget falls short of expectations, the best thing to do to "balance the books" is: 

Abandon plans and cancel the event. 

Postpone plans until economic conditions are more favorable to hold the event. 

Consult with stakeholders to explore what grants and donations are available to the event. 

Adjust the numbers so the bottom line meets the event's financial goals. 

 Find a new financial consultant.