I'll get back to you on that.

Meaning

I need more time to consider your request or question before responding.

Examples

• John: 'Can you finish the report by tomorrow?'<br>
• Alice: '<b>I'll get back to you on that.</b> I need to check my schedule.'
• John: '<b>I'll get back to you on that</b> after I have a chance to review the data.'
• Alice: 'What's the status of the marketing campaign?'<br>