How should I stop PIP on renewal?

Hi there - I'm due to make a renewal for PIP next month.

I have bipolar 1 which in the last few years has become easier to manage and I no longer feel able to justify making a claim (I was getting enhanced rate for daily living). I also have enough income to cover what I would lose. The thought of applying again and risking misleading the DWP is currently making me anxious. Also I haven't been able to secure a strong supporting statement.

How do you recommend me informing the DWP so that I'm not asked awkward questions about when and how my condition improved and why I didn't inform them sooner? Do I need to give a reason for why I'm not claiming or will they just accept it. Thanks.