diff --git a/ntp_core.c b/ntp_core.c
index 44682ec..99360de 100644
--- a/ntp_core.c
+++ b/ntp_core.c
@@ -3024,6 +3024,16 @@ NCR_ModifyMinstratum(NCR_Instance inst, int new_min_stratum)
 
 /* ================================================== */
 
+void
+NCR_ModifyOffset(NCR_Instance inst, double new_offset)
+{
+  inst->offset_correction = new_offset;
+  LOG(LOGS_INFO, "Source %s new offset %f",
+      UTI_IPToString(&inst->remote_addr.ip_addr), new_offset);
+}
+
+/* ================================================== */
+
 void
 NCR_ModifyPolltarget(NCR_Instance inst, int new_poll_target)
 {
diff --git a/ntp_core.h b/ntp_core.h
index 5c5a614..67971ea 100644
--- a/ntp_core.h
+++ b/ntp_core.h
@@ -113,6 +113,8 @@ extern void NCR_ModifyMaxdelaydevratio(NCR_Instance inst, double new_max_delay_d
 
 extern void NCR_ModifyMinstratum(NCR_Instance inst, int new_min_stratum);
 
+extern void NCR_ModifyOffset(NCR_Instance inst, double new_offset);
+
 extern void NCR_ModifyPolltarget(NCR_Instance inst, int new_poll_target);
 
 extern void NCR_InitiateSampleBurst(NCR_Instance inst, int n_good_samples, int n_total_samples);
diff --git a/ntp_sources.c b/ntp_sources.c
index 590e5e0..0dfdefb 100644
--- a/ntp_sources.c
+++ b/ntp_sources.c
@@ -1444,6 +1444,20 @@ NSR_ModifyMinstratum(IPAddr *address, int new_min_stratum)
 
 /* ================================================== */
 
+int
+NSR_ModifyOffset(IPAddr *address, double new_offset)
+{
+  int slot;
+
+  if (!find_slot(address, &slot))
+    return 0;
+
+  NCR_ModifyOffset(get_record(slot)->data, new_offset);
+  return 1;
+}
+
+/* ================================================== */
+
 int
 NSR_ModifyPolltarget(IPAddr *address, int new_poll_target)
 {
diff --git a/ntp_sources.h b/ntp_sources.h
index 79daf1d..89a322e 100644
--- a/ntp_sources.h
+++ b/ntp_sources.h
@@ -140,6 +140,8 @@ extern int NSR_ModifyMaxdelaydevratio(IPAddr *address, double new_max_delay_rati
 
 extern int NSR_ModifyMinstratum(IPAddr *address, int new_min_stratum);
 
+extern int NSR_ModifyOffset(IPAddr *address, double new_offset);
+
 extern int NSR_ModifyPolltarget(IPAddr *address, int new_poll_target);
 
 extern int NSR_InitiateSampleBurst(int n_good_samples, int n_total_samples, IPAddr *mask, IPAddr *address);
diff --git a/refclock.c b/refclock.c
index 44ba6d5..22d775a 100644
--- a/refclock.c
+++ b/refclock.c
@@ -321,6 +321,22 @@ RCL_ReportSource(RPT_SourceReport *report, struct timespec *now)
   }
 }
 
+int
+RCL_ModifyOffset(uint32_t ref_id, double offset)
+{
+  unsigned int i;
+
+  for (i = 0; i < ARR_GetSize(refclocks); i++) {
+    RCL_Instance inst = get_refclock(i);
+    if (inst->ref_id == ref_id) {
+      inst->offset = offset;
+      LOG(LOGS_INFO, "Source %s new offset %f", UTI_RefidToString(ref_id), offset);
+      return 1;
+    }
+  }
+  return 0;
+}
+
 void
 RCL_SetDriverData(RCL_Instance instance, void *data)
 {
diff --git a/refclock.h b/refclock.h
index 7947b62..40c852d 100644
--- a/refclock.h
+++ b/refclock.h
@@ -68,6 +68,7 @@ extern void RCL_Finalise(void);
 extern int RCL_AddRefclock(RefclockParameters *params);
 extern void RCL_StartRefclocks(void);
 extern void RCL_ReportSource(RPT_SourceReport *report, struct timespec *now);
+extern int RCL_ModifyOffset(uint32_t ref_id, double offset);
 
 /* functions used by drivers */
 extern void RCL_SetDriverData(RCL_Instance instance, void *data);
diff --git a/stubs.c b/stubs.c
index 044d17e..9d0f848 100644
--- a/stubs.c
+++ b/stubs.c
@@ -320,6 +320,12 @@ NSR_ModifyMinstratum(IPAddr *address, int new_min_stratum)
   return 0;
 }
 
+int
+NSR_ModifyOffset(IPAddr *address, double new_offset)
+{
+  return 0;
+}
+
 int
 NSR_ModifyPolltarget(IPAddr *address, int new_poll_target)
 {
@@ -419,6 +425,12 @@ RCL_ReportSource(RPT_SourceReport *report, struct timespec *now)
   memset(report, 0, sizeof (*report));
 }
 
+int
+RCL_ModifyOffset(uint32_t ref_id, double offset)
+{
+  return 0;
+}
+
 #endif /* !FEAT_REFCLOCK */
 
 #ifndef FEAT_SIGND