Leave the door open (for something or doing something) verb phrase
Make an opportunity available so that someone does something or something happens in the future
After the success of the first cooperation between two companies, they are going to leave the door open for the next one.
Today's offline meeting was very successful, so we left the door open for further meetings.
Nothing but fortunate chance
If you take a flyer (on something), you take a chance, risk, or gamble on it.
The last opportunity for one to achieve something
A second opportunity
Very little chance of succeeding in doing something
The verb "leave" should be conjugated according to its tense.