By removing one letter and rearranging the others (if necessary) to form a new word on each line, reduce the word INCREMENTAL down to the single letter A:

I N C R E M E N T A L
_ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _
_ _ _ _ _ _
_ _ _ _ _
_ _ _ _
_ _ _
_ _
A

Here is one SOLUTION.

ONE SOLUTION:

INCREMENTAL >
MERCANTILE >
INTERLACE >
CLARINET >
CENTRAL >
TRANCE >
ENACT >
NEAT >
TEA >
AT >
A

Did you come up with a different series of words? Please post your list in the comments. Thanks!