if so

if so

If (something) happens. The phrase is typically used at the beginning of a sentence. I think it's supposed to rain tomorrow. If so, the game will have to be postponed. A: "I'm worried that Sharon ruined the surprise." B: "Oh well. If so, we'll just have to regroup and come up with something else."
See also: if
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

if so

if that is [the case]; if that is so. She might be late. If so, we will eat without her. She is supposed to be all right. If so, we have nothing to worry about.
See also: if
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
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