make owner changable if position is unset

init.lua

@@ -290,8 +290,8 @@ local function compass_use_callback(itemstack, user, pointed_thing)
     local meta = itemstack:get_meta()
     local owner = get_compass_meta_owner(meta)
     local player_name = user:get_player_name()
-    if owner == "" then
-        -- set first user as owner
+    if owner == "" or not get_compass_meta_pos(meta) then
+        -- set first user as owner or change it if pos is unset
         set_compass_meta_owner(meta, player_name)
     elseif owner ~= player_name then
         -- already has owner