This was my intention:

You may make one change, and/or scramble the letters.

A change would be to delete a letter from the existing ones, to add a letter to the existing ones, or to swap one for another.

Examples:

PARTY can become PART. We deleted a letter.
PARTY can become TRAPS. We swapped a Y for an S.
PARTY can become PARITY. We added a letter.
PARTY cannot become TRAMPS because that is making two changes - deleting the Y and adding the M.

Just focus on making one change, and the scrambling (reordering) of the letters does not count as the change, only the addition or deletion or swap does.