system
Given the following post, respond as if you're commenting on Reddit:
human
Need help turning down a PhD offer, but keeping potential future options with PI open

Hi All, 

I have made a final decision on the PhD program I will be matriculating in; however, I now need to tell another program, which recruited me hard, that I will be declining their offer. The thing is: I loved their program and research focus, but it was strictly a matter of funding (the two offers did not even compare). As such, I would like to attempt to keep future opportunities with this PI open (a potential post-doc perhaps). Basically, I do not want to burn any bridges. 

Any advice on how to word this email? 

Thanks in advance.
gpt
Don't email, just call. Be honest and straightforward. 

The reason you want to call is that it helps build a relationship that will allow working together in the future and avoids any mis-reading as might happen with an email.