Take your time.
慢慢来

No rush/hurry.
不着急

Don't rush into it. /Don't rush into anything.
别草率行事

There's no reason/need to hurry/rush.
没必要着急

Don't be in such a hurry/rush.
别这么着急

Don't be so impatient.
别这么没耐心

We have plenty of time.
我们有足够的时间。

Take it easy.
放轻松

Calm down.
冷静点

Relax.
放松

No need to rush yourself.
没必要让自己太着急

What's the rush/hurry/emergency?
什么事情这么匆忙？/着急？/紧急？

Why are you in such a rush/hurry?
你为什么这么着急？

Why the big hurry?
为什么这么急？

Dialogue1:
A: Don't worry, take your time.
别着急，慢慢来。

B: I'm glad we left early, so we wouldn't have to rush.
很高兴我们早早就出门了，这样就不必着急了。

Dialogue2:
A: Calm down. What's the rush?
冷静点儿，有什么好着急的？

B: Sorry, I'm just excited.
对不起，我只是太兴奋了。

Dialogue3:
A: Take your time deciding. Don't rush into anything.
等等再做决定，别着急。

B: Thanks. I'll be sure and consider everything you mentioned.
谢谢，我一定会考虑你的话。

Dialogue4:
A: Slow down, patience is virtue.
慢点儿，忍耐是一种美德。

B: Yeah, well, silence is golden. Be quiet.
知道了，沉默是金，安静点儿。

Dialogue5:
A: I'll be done soon.
我一会儿就好了。

B: No hurry. Just let me know when you are finished.
不着急，你结束了告诉我就行。