Merge two columns in one column in sharepoint list

Hi,

I have a sharepoint list with 10 columns and due to revised requirements. we have to merge data 2 columns into 1 and remove other two columns.

Ex: Current structure(we have close to 200 entries)

First Name   Last Name   Age  --->  required   Name Age.

we have update data for existing records and only want New structure for any new entries.

Hoping to hear from you.

Regards,

Yash