remove unwanted specific line range

Hello everyone...I have large txt file and I would like to remove unwanted specific line.
My data is like this:

So I would like to remove from line below No. until line reassambled like this:

Thanks...

Try:

perl -p0e 's/(?<=No\. Time\n).*?Reassembled\n//sg;s/\n\n/\n/g' file

Hi taxi,

An option using sed:

sed -e '/No. Time/,/Reassembled/d;s/^$/No. Time/' taxi
No. Time
0000 48 4f 4b 0d HTTP/1.1 200 OK.
0010 0a 30 20 4e .Date: Sat, 20 N
No. Time
0000 48 54 54 2c HTTP/1.1 200 OK.

Regards

thank you for your reply. Based on my input, both given output that I have mention earlier. But my original file just not No. and Time only, but other text with space each other.
No._5space_Time_8space_Source_16space_Destination__11space__Protocol Info

I'm try to put all string in line No., but it's remove this line.

taxi,
If the input is something like this (and the headers always begin with "No"...):

No.     Time        Source                Destination           Protocol Info
38 1.292367
Frame

0000 00 04 45 00 ..."Z.... l...E.
0010 01 05 0a 01 ...L@.@..?......

Reassembled

0000 48 4f 4b 0d HTTP/1.1 200 OK.
0010 0a 30 20 4e .Date: Sat, 20 N

No.     Time        Source                Destination           Protocol Info
61 1.416360
Frame
0000 00 04 e2 22 ..."Z.... l...E.
...
Reassembled
0000 48 54 54 2c HTTP/1.1 200 OK.

Yo can try with:

Vstr:~$ X=$(awk '/^No/{print;exit}' input)
sed -e "/$X/,/Reassembled/d;s/^$/$X/" input
No.     Time        Source                Destination           Protocol Info
0000 48 4f 4b 0d HTTP/1.1 200 OK.
0010 0a 30 20 4e .Date: Sat, 20 N
No.     Time        Source                Destination           Protocol Info
0000 48 54 54 2c HTTP/1.1 200 OK.

Regards