Removing fixed match from Safe Harbor Plan

Hello.

Client is looking to remove a fixed non-safe harbor match of 100% of deferrals up to 6% comp(pay period determination period) from its plan.  The plan also has a safe harbor match., so this is a safe harbor plan.   Can we removed the fixed match so long as it is done prospectively (say 8/1/21) with no SH notice provided by July 1.    Is this change a permissible mid-year change to a SH plan?  Please advise.