A speaker may leave the object of a conditional expression initially indeterminate so that the audience anticipates its clarification in the consequence. The delay becomes a means of directing attention rather than merely a lack of words.
For example, a statement equivalent to “If I wished to ...” can postpone its specific content until the second clause. But the postponed explanation must actually clarify the meaning; unresolved ambiguity is not an independent virtue.
This use of initial suspense followed by clarification must be distinguished from omission that simply avoids needless repetition.