diff --git a/goodtimes/services.py b/goodtimes/services.py
index 13b5a81..263cb21 100644
--- a/goodtimes/services.py
+++ b/goodtimes/services.py
@@ -147,6 +147,7 @@ class SMSService:
             raise SMSError(message=str(e))
 
     def create_otp(self, principal: IAmPrincipal, opt_purpose: str):
+        old_otp_change = IAmPrincipalOtp.objects.filter(principal=principal).update(is_used=True)
         otp = IAmPrincipalOtp.objects.create(
             principal=principal, otp_purpose=opt_purpose
         )