She stopped replying mid-conversation.

The thing to give up on is finding out why. Whatever the reason was, she is not going to type it, and asking turns a quiet thread into a conversation about the thread. What is left is the only part you control: what the next message is like to receive. A conversation that died of nothing can be restarted by anything, as long as the anything does not mention the dying.

The same evening

A reply that does not come within the hour is not a silence yet. Mid-conversation, people get pulled away: a call, dinner, a friend, a phone at two percent. Sending anything now, even a joke, tells her you were watching the screen. Let the evening end without you. Most threads that stop like this start again on their own by the next day.

Day two or three

This is the window to restart it. The gap is long enough to be real and short enough that the thread is still warm and she remembers what you were talking about. Send one message, and make it stand on its own: something to reply to that has nothing to do with why she stopped.

After a week

The old thread is cold. Do not pick up where it stopped, and do not mention the gap at all, because a joke about her silence a week later reads like a grudge you carried. Start a new conversation with something new, a thing that happened or a question that needs no history.

Your restart got nothing either

Stop here. Two unanswered messages in a row is the limit, and a third reads as chasing. It also changes how she remembers the whole conversation, the good part included. If she comes back, she knows where to find you, and you lead again from there.

You are naming the silence, lightly. Someone who was enjoying the conversation will play along; someone who had already moved on will not answer, and that is the same answer you were already holding. What it does not do is show her you were counting the days.

She plays along

The restart worked. Answer in kind for a message or two, then move the conversation forward instead of back: do not ask where she went, and do not let the bit run forever. A thread that died once dies easier the second time, so steer toward a plan while the energy is up.

She apologises and explains

Accept it in a line and move on. "No worries" and something new is enough. Do not reassure her at length and do not dig into the reason. The explanation is hers to give or not, and dwelling on it makes the silence the topic again.

A short, polite reply

She answered out of courtesy rather than interest. Match her length and give it one more honest try with something easy to answer. If that lands flat too, let it rest. You have not lost anything you had.

Nothing

That is the answer, and it came in one message instead of a week of wondering. Do not follow up the follow-up, and do not unmatch to make a point. If she reappears later, treat it as a fresh start and keep the old silence out of it.

What should I text a girl who hasn't replied in a few days?

One light message that gives her something new to answer, without asking why she went quiet. A playful frame works better than a question about the conversation, because stepping back into a game costs her nothing.

How do I restart a conversation after she stopped replying without looking needy?

Do not mention needing a reply, do not ask whether she got your message, and do not apologise. Send something that would be fun to receive from anyone, and send it once.

Is this the same as being left on read?

Close, but not the same. Left on read means she opened your message and chose not to answer. A conversation that stops mid-flow more often dies of distraction than of a decision, which is why a restart works more often here.

Should I double text her?

One message after a real gap is not the double texting people warn about. Two unanswered messages in a row is the limit. A third tells her the silence has become the most interesting thing about you.

What if she stopped replying right after I asked her out?

Then the thread did not die of nothing. The silence is her answer to the invitation, and a restart joke will read as if you missed it. Do not repeat the ask. If she wants to meet, she can pick it up.

How long should I wait before texting her again?

Two or three days for a conversation that stopped mid-flow. Under a day, you are reacting to a delay rather than a silence. Past a week, you are starting a new conversation, so leave the old one out of it.