Google Scripts: Copy cell if

i know there are already many topics like mine, but i am completly new on programming scripts and therefore i ask you to help me with following problem:

In cell B2 is the user name and in cell C2 the submitter type - if the submitter type is "Requester" then the user name of cell B2 should be copied to cell AE2 - the problem is, that i also want to keep the previous user names if the submitter type change...

That means, first the submitter type is "Requester" then the system should copy the user name to cell AE2 - if the submitter type of my line change, then the already copied user name should not change - understood what i want? This should work for all lines of the spreadsheet...