That’s exactly what I did to save some cash & had no problems. Class 1 May 2003, lapsed May 2004 but continued using class 2, new class 1 last week with local AME.
Your circumstances may be different wrt age/validities. Have a good look at your medical certificate – it states ‘A class 1 medical certificate is acceptable for Class 2 privileges and validities’ and opposite there is a ‘summary of minimum periodic requirements’. Apply the class 2 requirements to your examination date to check that Class 2 privileges are still covered.
Certificate also lists a JAR-FCL reference for the full rules. If still any doubt, suggest you give the CAA a call to check.