diff --git a/Grid/simd/Grid_a64fx-fixedsize.h b/Grid/simd/Grid_a64fx-fixedsize.h
index a8c2b978..232c2933 100644
--- a/Grid/simd/Grid_a64fx-fixedsize.h
+++ b/Grid/simd/Grid_a64fx-fixedsize.h
@@ -436,12 +436,12 @@ struct PrecisionChange {
     vecf sb_v = svcvt_f32_x(pg1d, b);
     return svuzp1(sa_v, sb_v);
   }
-  static inline void StoD (svfloat32_t s,svfloat64_t &a,svfloat64_t &b) {
+  static inline void StoD (vecf s,vecd *a,vecd *b) {
     pred pg1d = acle<double>::pg1();
     vecf sa_v = svzip1(s, s);
     vecf sb_v = svzip2(s, s);
-    a = svcvt_f64_x(pg1d, sa_v);
-    b = svcvt_f64_x(pg1d, sb_v);
+    *a = svcvt_f64_x(pg1d, sa_v);
+    *b = svcvt_f64_x(pg1d, sb_v);
   }
   static inline vech DtoH (vecd a,vecd b,vecd c,vecd d) {
 /*