Validation on Person Number while converting a pending worker record

Summary:

Hi All,

We have a requirement where we want to put a Validation on the Person Number field when the user is Converting the Pending Worker record.

When we create a Pending Worker record, system assigns a dummy unique value (Customization done by us) and this dummy value has a format of Initials of logged in user+Sysdate with timestamp. and once the Pending worker is created with this Dummy person number, another system updates the Dummy value with the actual person NUmber.

Our requirement is to restrict the users converting the PW records while the record has this Dummy value. They should only be ablr to convert if the Person Number is in the format for example A12345 and not the dummy value for example pk29-03-2022 03:10 PM.