Getting experience letter from a previous employer

Hi all! I just posted a similer question but don't know how to edit it after the submittion. I did some research so here's the updated question. I'm about to switch employer and wondering if it's possible to get a experience letter from the current employer after leave the firm. I will have my final section of CPA exam after I leave the firm, so this problem will pop up when I applying full disclosure license. I'm in audit practice with the current firm and will be in tax in the new firm. Any suggestions will be welcomed here, thanks in advance!