Dear Sir/Madam,
Most humbly, I beg to state that I am ________ (name) working as a __________ (job profile) having employee ID __________ (mention number).
As discussed earlier, I was supposed to follow up with you regarding the ___________ (project/report/any other). I would like to offer my deepest apologies for not following up due to ______________ (mention reason – illness/work pressure/any other).
I hope that you will accept my apology and arrange a meeting to discuss the progress of the ongoing project. If you wish to contact me at any point, you can reach me at ________ (contact details).
Warm Regards,
___________ (Name),
___________ (Contact details)