Email to my boss

Hi ,

Can you please correct the paragraphss if not correct ?

Regards,
William

I had stepped out to the washroom when they pinged me. It was my mistake. I should have informed them before stepping out for a break. I will see to it that I inform them before going out henceforth.

One more thing I need to bring to your notice is that yesterday they wanted someone senior to join the call even though I was a part of it and responding to them. However, none of them answered and hence the call was rescheduled to the evening time.

The 2nd paragraph is still a little garbled, I’m not totally sure what you mean.
You have made punctuation spacing errors again.
You have not made clear here who ‘them’ is. I assume you make it clearer earlier in the mail.

A more natural version of your paragraphs would be:

When they pinged me I was in the washroom so did not hear it. This was my mistake as I should have informed them before taking a break. I will inform them in future.
In addition, yesterday they said they wanted someone senior to join the call. I was involved in the call but could not receive an answer so it was rescheduled for later that day.

Hi Beeesneees,

Thanks for corrections.

Your paragraph sounds professional and perfect.

Regards,
William