If a whole tzitzit of one corner comes off all the strings and they aren’t there anymore are you allowed to put new string new tzizit there or is it pasul simple Sephardic bottom line Halacha

The garment remains valid (kasher) and you are permitted — and required — to re-attach new tzitzit to that corner. Removing or losing one corner's strings does not permanently invalidate the tallit or tallit katan; you simply tie a new set of strings to that corner and the garment is fully kosher again. This is the straightforward Sephardic ruling.

Key Takeaways

A garment that loses all the strings from one corner is not permanently invalidated — it simply lacks tzitzit on that corner.
You must re-tie new strings to that corner to make the garment wearable again with a beracha.
The new strings must be spun lishmah (for the sake of the mitzvah) to be valid [Shulchan Arukh, OC 11:1].
Until re-tied, you may not wear the garment with a beracha, as a four-cornered garment without proper tzitzit on all corners is invalid.
The tallit itself is not "burned" or permanently pasul — only the missing corner needs correction.

Detailed Halachic Analysis

The Core Rule: Garment vs. Strings

The mitzvah of tzitzit is on the garment, not permanently embedded in it. The Torah commands:

"וְעָשׂוּ לָהֶם צִיצִת עַל־כַּנְפֵי בִגְדֵיהֶם" — "They shall make for themselves fringes on the corners of their garments" [Numbers 15:38].

This means the tzitzit are an attachment to the garment. If they fall off, the garment simply needs new ones attached.

What Makes a Garment Pasul vs. Fixable?

The [Shulchan Arukh, Orach Chayim 11] discusses at length the requirements for the tzitzit strings themselves. The key principle is:

The strings must be spun lishmah — with intent for the sake of the mitzvah.
They must be twisted/spun properly (shezurah).

None of these requirements "die" with the garment. When you attach new, valid strings, the garment becomes fully kosher.

Can You Re-Attach to the Same Corner?

Yes. The [Shulchan Arukh, OC 15] rules that if tzitzit fall off, you may re-tie them. The only concern would be if the hole in the corner itself was torn or moved out of the valid halachic range — but that is a separate issue about the garment, not the strings.

Sephardic Specific Notes (Following Maran)

Maran [Shulchan Arukh, OC 11:1] rules that strings spun by a non-Jew are:

Invalid according to the Rambam
Valid according to the Rosh if a Jew supervises

The Sephardic ruling follows the Rambam — so when you buy new strings, make sure they are certified as spun lishmah by a Jew. This is the standard for Sephardim and pre-made tzitzit strings sold today generally meet this requirement.

Practical Bottom Line for Sephardim

✅ Your tallit or tallit katan is not permanently pasul.
✅ Buy new tzitzit strings (pre-made sets are readily available and certified lishmah).
✅ Tie them onto that corner following the standard Sephardic tying method.
✅ Once all four corners have valid tzitzit, you may wear the garment again with a beracha.
❌ Do not wear the garment as a four-cornered garment without re-tying — you would be wearing a garment obligated in tzitzit without fulfilling the mitzvah.

For personal guidance on the specific tying method or if there is any damage to the corner of the garment itself, consult your local rabbi or posek.