Is it really necessary to give the first few sentences of the call? If the readers already know what the report is about (having just seen it actually happen), then it's redundant to hash it out again. Just have the character pick up the phone "to call the police," and skip to the next scene.
On the other hand, if it's a deliberate false report to the police, you might want to show that. Even then, though, it might be better shown in the same way—skipping over the call entirely, and leaving the reader to discover as the officer reports to the chief that the incident was falsely reported on the phone.
If the incident is something only learned about through the call, then you would want to show the whole conversation, so that doesn't apply here. (One book I read begins, "I'd like to report a bomb," and proceeds through the entire 9-1-1 call, with accurate scripting checked by a police despatcher.)
I can't think of any case where it would really add something to the story to show the first few sentences of a 9-1-1 call but not the whole thing. So you should ask yourself if it really adds anything to the story.
A break between paragraphs should be sufficient in any case to indicate the gap.