Md. Code, Family Law § 10–351

If a child support order issued by a tribunal of this State is modified by a tribunal of another state which assumed jurisdiction pursuant to the Uniform Interstate Family Support Act, a tribunal of this State:

(1) may enforce its order that was modified only as to arrears and interest accruing before the modification;

(2) may provide appropriate relief for violations of its order which occurred before the effective date of the modification; and

(3) shall recognize the modifying order of the other state, upon registration, for the purpose of enforcement.