diff --git a/57.md b/57.md
index cb1f126..438a0f8 100644
--- a/57.md
+++ b/57.md
@@ -168,7 +168,7 @@ A client can retrieve `zap receipt`s on events and pubkeys using a NIP-01 filter
 
 ### Appendix G: `zap` tag on zapped event
 
-When an event includes a `zap` tag, clients SHOULD calculate the lnurl pay request based on it's value instead of the profile's field. An optional third argument on the tag specifies the type of value, either `lud06` or `lud16`.
+When an event includes a `zap` tag, clients SHOULD calculate the lnurl pay request based on its value instead of the profile's field. An optional third argument on the tag specifies the type of value, either `lud06` or `lud16`.
 
 ```json
 {