The LTR 2645C is an interim response telling you the IRS received your correspondence but needs more time to process it. Like the LTR 264C, it's a "please wait" letter. The IRS hasn't forgotten about your inquiry — they just haven't gotten to it yet.
What to Do
Wait. The letter provides a timeframe, typically 30 to 60 days. Don't call the IRS before that period expires unless you have an urgent situation that can't wait (pending levy, expiring deadline, financial hardship).
After the stated period passes, if you haven't received a substantive response, call the number on the LTR 2645C. Have your original correspondence and the delay letter ready for reference.
When to Escalate
If you receive multiple LTR 2645C letters for the same inquiry without resolution, consider contacting the Taxpayer Advocate Service. Repeated delay notices without substantive action indicate a processing failure that TAS can help resolve.
If IRS processing delays are causing you problems, call us at (813) 229-7100.