Phone Data Validation

Dear Sir,

The Phone number validation by default requires that it should not be less than 9 characters. However in Singapore, the local numbers are 8 characters only.

Is there a way to edit the relevant files to reduce this to 8 instead of 9 characters?
Otherwise, it will always be shown as “Phone Number Is Not Correct” during the submission by a new booking.

Appreciate some tips / advise.

Thank you,
Michael