Drop letter, add letter ..

grail - agile

Agile - Gavel

Gavel - large

large - eagle

Eagle - glean

glean - bagel

Bagel - lager

lager - gavel

Gavel - angle

angle - gleam

Gleam - ample

Ample - Psalm

Psalm - Maple

Maple - meals

Meals - Blame

blame - amber

Amber - Camber ( Camber refers to a slight curve, arch, or tilt in a surface or component, )

Camber - bracer

Oops, we've added a letter. I'll go back to "amber."

amber - bread

Bread - Derby

derby - robed

robed - coder