The phrase "a call that could" is correct and usable in written English.
It can be used when discussing a potential action or decision that may have significant implications or outcomes.
Example: "This is a call that could change the course of our project if we decide to move forward."
Alternatives: "a decision that might" or "a request that has the potential to".
Again, it was a call that could have gone either way.
And now, Diego da Silva Costa is waiting for a call that could make him a World Cup-winning striker.
This is the second time in nearly two years the Tigers have been hurt a call that could have been changed by video replay, but thankfully, the error wasn't as devastating this time around.
There is no clock on the screen -- only verbal warnings about time remaining, from the booth -- as a referee makes a call that could enrage 75,000 fans simultaneously.
The call for a "basic change of values" in connection to the environment (a call that could be interpreted in terms of either instrumental or intrinsic values) reflected a need for the development of environmental ethics as a new sub-discipline of philosophy.
The internal structures of the crest of Corythosaurus are quite complex, making possible a call that could be used for warning or attracting a mate.
Then I think of how they'd live with knowing that a phone call they made--a call that could have waited--led to tragedy.
For the romantic challengers, by contrast, "politics" was a calling that could be mentioned in the same breath as "honor" — both qualities were integral to their quirky personalities, and their personalities were integral to their quirky campaigns..
For the romantic challengers, by contrast, "politics" was a calling that could be mentioned in the same breath as "honor" — both qualities were integral to their quirky personalities, and their personalities were integral to their quirky campaigns...
Steven Soderbergh won the best-director prize for "Traffic"—a close call that could have gone another way.
Other states have rightly adopted new laws to prevent people from avoiding a phone call that could save a life for fear of being arrested.
