Md. Code, Family Law § 10–364

(a) A tribunal of this State may not modify a Convention child support order if the obligee remains a resident of the foreign country where the support order was issued unless:

(1) the obligee submits to the jurisdiction of a tribunal of this State, either expressly or by defending on the merits of the case without objecting to the jurisdiction at the first available opportunity; or

(2) the foreign tribunal lacks or refuses to exercise jurisdiction to modify its support order or issue a new support order.

(b) If a tribunal of this State does not modify a Convention child support order because the order is not recognized in this State, § 10–361(c) of this subtitle applies.