The same three letters, in the same, consecutive order, can change each of the words below into new ones. Once you solve the puzzle, try to think of a clever title for it - and notice the one the constructor came up with, as shown below.  

TEN
HEM
PAGE
GALL
ELOPE
SERGE

Answers:

The letters are ANT:

TENANT
ANTHEM
PAGEANT
GALLANT
ANTELOPE
SERGEANT

Credit: NY Times Crossword
March 8, 1998
Richard Silvestri
WHAT A NICE PICNIC!  [no ants!]