Answered by Ustadh Tabraze Azam
Question:  When one’s fast is invalidated by an accident, how does one behave? Can they eat and drink or do they act like how you have described how a person who deliberately breaks their fast should. I.e. by refraining from food and drink.  When fasting outside of Ramadhan, does my intention have to be made when I wake up for suhoor? Or can it be made by mid day?  When fasting in ramadhan and one does not wake up for suhoor but had the intention to fast and wake up, is their fast valid? And what is the case for fasts outside ramadhan? Is suhoor necessary for one to be able to fast?
Answer: Wa alaikum assalam wa rahmatullahi wa barakatuh,
I pray that you are well, insha’Allah.
 If you accidentally do something that breaks your fast (e.g. water going down throat whilst gargling), it would be obligatory to continue to abstain from food and drink.
 The intention to perform a voluntary fast can be made until the Islamic midday (the half way point between dawn and sunset)
 The pre-dawn meal (suhur) is not a condition for the validity of one’s fast.
[Shurunbulali, Maraqi al-Falah; `Ala al-Din `Abidin, al-Hadiyya al-`Ala’iyya]
And Allah alone gives success.
Checked & Approved by Faraz Rabbani