2 Scenarios, howto record?

[Omer Hayat]

I'm relatively new to acctg, need help in a few entries.

Scenario 1: I pay a vendor thru a PDC. recorded normally.
now when the date arrives to deposit the check, i donot have sufficient amt in bank, therefore ask vendor to not deposit it and promise to pay him in installments. How will this be recorded? also the installments? The vendor holds the check as security till the installments are paid.

Scenario 2: buy something relating to a job for which the customer will pay me later on after the job. how to record the expense and then the reimbursement?

thanks!