How to sign: hold back or set aside, especially for future use or contingency
"they held back their applause in anticipation";
Categories: keep back, withhold
Within this category: devote
How to sign: give or assign a share of money or time to a particular person or cause
"I will earmark this money for your research";
Similiar / Same: appropriate, earmark, set aside, allow
Categories: allot, assign, portion
How to sign: an athlete who plays only when another member of the team drops out
Similiar / Same: substitute
Within this category: bench warmer, pinch hitter
How to sign: arrange for and reserve (something for someone else) in advance
"reserve me a seat on a flight"; "The agent booked tickets to the show for the whole family"; "please hold a table at Maxim's";
Categories: bespeak, call for, quest, request
Within this category: keep open