Once the settings are created, there is no option to edit the settings, need to delete the settings which are created earlier and create new settings with the updated limits

Follow the below path to delete the settings

Settings --> Expenses Management --> Petty Cash Approval Settings --> Select the Branch, Type and click on Get --> Click on Delete icon against the branch

Follow the below path to Create the new settings

Settings --> Expenses Management --> Petty Cash Approval Settings --> Select the Branch, Type and click on Get --> Click on + Symbol against the Branch --> Update the required fields --> Save