Over a one of a suit opener with partner responding at the one level a rebid of 1NT = 15 to 17, 2NT = 18/19.
If partner bids 2 over 1 then 2NT = 15 to 19 and is game forcing. If partner's response is at the one level and there is interference at the 2 level from the fourth seat what now is the value of opener's 2NT rebid? Is it 18/19 game forcing as the 1NT bid showing 15 to 17 is not available? If so what should opener rebid?