collect (one's) thoughts
To pause and think before speaking or taking action. Can I please just have a second to collect my thoughts before I respond? Susie paused to collect her thoughts and come up with a tactful response to her seething sister.
collect one's thoughts
Fig. to take time to think through an issue; to give some thought to a topic. I'll speak to the visitors in a moment. I need some time to collect my thoughts.