Material alteration is the standard used for evaluating amendments to marks in all phases of registration process. Each case must be decided on its own facts, and the general rules are subject to many exceptions. The controlling question is always whether the old and new forms of the mark create essentially the same commercial impression.
Examples of Material Alteration of Trademark Found (i.e. Change not permitted):
GOT STRAPS to GOT STRAPS?
TACILESENSE” to “TACTILESENSE
Adding "MR. SEYMOUR” to design mark
Examples of No Material Alteration of Trademark Found:
FREEDOMSTONE to FREEDOM STONE
NY JEWELRY OUTLET to NEW YORK JEWELRY OUTLET
GRAN VINO MALAGA LARIOS (plus design) to VINO DE MALAGA LARIOS (with similar design)