Solution need to this situation (re-timed subtitle)

[Hiddengibbon]

I have a subtitle. It's timing is constant delay.
Example,
1st line : 00:01:000 -> 00:01:990
2nd line : 00:02:000 -> 00:02:990
3rd line : 00:03:000 -> 00:03:990

I found it's delay about 200 ms.
So I open it in SubResync and retime the 1st line from 00:01:000 to 00:00:800.
So it's change to :
1st line : 00:00:800 -> 00:01:790
2nd line : 00:01:800 -> 00:02:790
3rd line : 00:02:800 -> 00:03:790

If I don't want this, I just want to change the start time only (end time is remain the same)
This is what I want :
1st line : 00:00:800 -> 00:01:990
2nd line : 00:01:800 -> 00:02:990
3rd line : 00:02:800 -> 00:03:990

Are there any solution ?

There're few hundred of line so I can't open it in SubtitleWorkshop and retime it one-by-one.

All suggestion are appreciate.

Best Regards,

[AlanHK]

First shift all the times up by 200 ms as you did earlier.

In Subtitle Workshop:
Edit/Timings/Time Expander
Expand all durations by 0,200.

Unselect the two "only" conditions, but leave "prevent overlap" just in case.

Subtitle Workshop has a lot of clever functions for adjusting times. Reading the help will be rewarding.

[Hiddengibbon]

First shift all the times up by 200 ms as you did earlier.

In Subtitle Workshop:
Edit/Timings/Time Expander
Expand all durations by 0,200.

Unselect the two "only" conditions, but leave "prevent overlap" just in case.

Subtitle Workshop has a lot of clever functions for adjusting times. Reading the help will be rewarding.

Million thanks for your reply