is there anyway to sleep the some particularthread by name or some any other source
in case I've two threads
Thread call = new Thread(() => open_page(txtbx_1.Text));
call.Start();
Thread call_2nd = new Thread(() => open_page(txtbx_1.Text));
call_2nd.Start();
I want to sleep call and call_2nd for at least 15 minutes(but don't want to sleep the main Thread.
Thanks

No - you can't ask another thread to sleep. Apart from anything else, at the time when you want it to sleep it may hold a lock or other resource which really shouldn't be held while sleeping.
You'd have to do this cooperatively, with some sort of shared data between the threads indicating what you want to sleep and for how long. Alternatively, schedule a timer to only start the relevant activity after a certain length of time.
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