We have to update pay frequency (Semimonthly to Biweekly for an existing Paygroup instead of create

Summary: We have requirement is like to transfer around 1100 employees from semimonthly to Biweekly by updating an existing pay group frequency instead of create new pay group. I know that to update an existing pay group pay frequency (Period Type) does not allow. but client don't want to create a new pay group to assign it to the employees. Client is using ADP payroll.

Please advise what is the best way and less impact solutions. If go with a New Pay group what is the OTL side impact? Client is using ERP finance also, will it impact finance side as well.