Ask for one named change — a fixed finish time, an earlier posting date, or a standing unavailable block — and say when you need the answer. Oregon puts a number on the posting date: employers with at least 500 employees worldwide in the retail, hospitality or food services industry must give the written schedule at least 14 calendar days in advance of the first day on it, the Oregon Bureau of Labor and Industries says. Below that size, or outside those industries, no posting date is set for you, so your request has to carry its own date.
Two cities and a state already put numbers on this
Oregon's 14 calendar days are only half of what that BOLI page lists. It also sets what the employer pays for changing a posted schedule: one hour at the regular rate of pay plus wages earned when the employer adds more than 30 minutes to a shift or moves a shift without cutting hours, and one-half times the regular rate for each scheduled hour not worked when the employer cuts or cancels. The same page says a covered employer must give a written good faith estimate at hire, stating the median number of hours you are expected to work in an average month.
Seattle's Secure Scheduling Ordinance uses the same 14 days for retail and food services establishments with 500 or more employees worldwide, with full-service restaurants covered once the company also has 40 or more full-service locations worldwide, the City of Seattle says. That ordinance page also requires the employer to post available hours for three days and offer them to current employees before hiring new ones, and to give the written good faith estimate of median hours at hire, annually, and on a significant change.
Look up your own city and state before you write. When no ordinance covers you, the numbers above still work as the shape of a request: a posting date, a median hours figure, a change rule.
Decide whether the problem is the hour or the notice
These are different asks and they go to different answers. "I never know until Saturday" is a notice problem, and the fix is a posting date and a median hours figure. "Tuesdays at 5 pm do not work" is an hour problem, and the fix is a fixed finish on one named day.
Pick one. A request that names both reads as a wish list, and the scheduler will grant the cheaper half. Oregon's page says an employee can identify limitations or changes in work schedule availability at hire and throughout employment, BOLI again — that is the channel for the hour problem, and it does not require you to explain why.
If you are still choosing, read what to ask about the schedule before you accept a job; the same three questions work on a current employer.
Example: a 4 pm Tuesday finish costs $9.50 a week
Example figures. You work 8 am to 4:30 pm on Tuesdays at $19 an hour and the pickup you have to make is at 4:45. Asking to finish at 4 pm gives up 30 minutes of paid time each Tuesday: 0.5 × $19 = $9.50 a week, or $494 across 52 weeks. Under the FLSA there is no overtime consequence either way, because the Department of Labor's overtime fact sheet sets the trigger at hours worked in excess of 40 in a workweek, paid at time and one-half.
Put the $9.50 in the message. A scheduler hearing "I would give up half an hour of pay each Tuesday to make this work" is being told the request is costed, not floated. If you would rather keep the hours, offer the swap instead: the same half hour added to a Thursday.
Send four lines, then write the follow-up date down
Send this, changed to your day, hour and date:
"Could my Tuesday shifts finish at 4 pm starting with the roster posted on the 20th? I can start at my usual time and take the half hour back on Thursdays. I need an answer before the 20th to confirm the pickup. If 4 pm is not possible, which Tuesday finish is?"
Then make one calendar entry for yourself, on the day the roster comes out: "20th — no reply yet on the 4 pm Tuesday finish? Ask [name] in person, and note the date I asked." A request with a date on it becomes a record; a request without one becomes a mood. If the answer is no and the pattern continues, keep a short factual log of each change and bring the log, not the feeling, to the next conversation.